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Tamilnadu State Board New Syllabus Samacheer Kalvi 12th Computer Applications Guide Pdf Chapter 6 PHP Conditional Statements Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 12th Computer Applications Solutions Chapter 6 PHP Conditional Statements

12th Computer Applications Guide PHP Conditional Statements Text Book Questions and Answers

Part I

Choose The Correct Answers

Question 1.
What will be the output of the following PHP code?
<?php
$x;
if ($x)
print “hi”;
else
print “how are u”;
?>
a) how are u
b) hi
c) error
d) no output
Answer:
c) error

Question 2.
What will be the output of the following PHP code ?
<?php
$x = 0;
if ($x++)
print “hi”;
else
print “how are u”;
?>
a) hi
b) no output
c) error
d) how are u
Answer:
a) hi

Question 3.
What will be the output of the following PHP code ?
<?php
$x;
if ($x == 0)
print “hi”;
else
print “how are u”;
print “hello”
?>
a) how are uhello
b) hihello
c) hi
d) no output
Answer:
a) how are uhello

Question 4.
Statement which is used to make choice between two options and only option is to be performed is written as
a) if statement
b) if else statement
c) then else statement
d) else one statement
Answer:
b) if else statement

Question 5.
What will be the output of the following PHP code ?
<?php
$a =
if ($a)
print “all”;
if
else
print “some”;
?>
a) all
b) some
c) error
d) no output
Answer:
c) error

Question 6.
What will be the output of the following PHP code ?
<?php
$a = “”;
if ($a)
print “all”;
if
else
print “some”;
?>
a) all
b) some
c) error
d) no output

Question 7.
What will be the output of the following PHP code ?
<?php
$x = 10;
$y = 20;
if ($x > $y + $y != 3)
print “hi”;
else
print “how are u”;
?>
a) how are u
b) hi
c) error
d) no output
Answer:
b) hi

Question 8.
What will be the output of the following PHP code ?
<?php
$x = 10;
$y = 20;
if ($x > $y && 1||1)
print “hi”;
else
print “how are u”;
?>
a) how are u
b) hi
c) error
d) no output
Answer:
b) hi

Question 9.
What will be the output of the following PHP code ?
<?php
if (-100)
print “hi”;
else
print “how are u”;
?>
a) how are u
b) hi
c) error
d) no output
Answer:
a) how are u

Part II

Short Answers

Question 1.
Define Conditional Statements in PHP
Answer:
Conditional statements are useful for writing decision-making logics. It is the most important feature of many programming languages, including PHP. They are implemented by the following types:

1. if Statement
2. if…else Statement
3. if…else if….else Statement
4. switch Statement

Question 2.
Define if statement in PHP.
Answer:
If a statement executes a statement or a group of statements if a specific condition is satisfied as per the user expectation.
Syntax:
if (condition)
{
Execute statement(s) if condition is true;
}

Question 3.
What is an if-else statement in PHP?
Answer:
If else statement in PHP:

1. If a statement executes a statement or a group of statements if a specific condition is satisfied by the user expectation.
2. When the condition gets false (fail) the else block is executed.

Syntax:
if (condition)
{
Execute statement(s) if condition is true;
}
else
{
Execute statement(s) if condition is false;
}

Question 4.
List out Conditional Statements in PHP.
Answer:

• if Statement
• if…else Statement
• if…else if….else Statement
• switch Statement

Question 5.
Write Syntax of the If else statement in PHP.
Answer:
if (condition)
{
Execute statement(s) if condition is true;
}
else
{
Execute statement(s) if condition is false;
}

Question 6.
Define if…elseif….else Statement in PHP.
Answer:

• If-elseif-else statement is a combination of if-else statement.
• More than one statement can execute the condition based on user needs.

Question 7.
Usage of Switch Statement in PHP.
Answer:

• The switch statement is used to perform different actions based on different conditions.
• Switch statements work the same as if statements but they can check for multiple values at a time.

Question 8.
Write Syntax of the Switch statement.
Answer:
switch (n)
{
case label1:
code to be executed if n=la bel1;
break;
case Iabel2:
code to be executed if n=label2;
break;
case label3:
code to be executed if n=iabel3;
break;
…
default:
code to be executed if n is different from all labels;
}

Question 9.
Compare if and if-else statement.
Answer:

Part III

Explain in brief answer

Question 1.
Write the features Conditional Statements in PHP.
Answer:
PHP Conditional statements:

1. Conditional statements are useful for writing decision-making logics.
2. It is most important feature of many programming languages, including PHP.
3. They are implemented by the following types:
4. if Statement
5. if…else Statement
6. if…elseif….else Statement
7. switch Statement

Question 2.
Write is the purpose of if elseif else stament.
Answer:

• A user can decide among multiple options.
• The if statements are executed from the top I down.
• As soon as one of the conditions controlling the if is true, the statement associated with that if is executed, and the rest of the ladder is bypassed.
• If none of the conditions is true, then the final else statement will be executed.
• More than one statement can execute the condition based on user needs.

Question 3.
Differentiate Switch and if-else statement.
Answer:

Question 4.
Write Short notes on the Switch statement.
Answer:

1. The switch statement is used to perform different actions based on different conditions.
2. It tests for equality only.
3. It uses default value when all the case values are not matched.
4. It can have multiple ease values.

Question 5.
Differentiate if statement and if-else statement.
Answer:

Part IV

Explain in detail

Question 1.
Explain Functions of Conditional Statements in PHP.
Answer:
Function Conditional Statements:

1. Function conditional statement is the function specified inside the conditional statements.
2. We can’t call a conditional function before its definition.

Syntax:
if(expression)
{
function function_name( )
{
block of statements;
}
}
function_name( ); // calling function.
Eg:
<? php
display( );
if(TRUE)
{
function display( )
{
echo “condition and function”;
}
}
Output: condition and function

Question 2.
Discuss in detail about Switch statement with an example.
Answer:

• The switch statement is used to perform different actions based on different conditions.
• Switch statement test only for equality.
• Switch statement execute one case after another till a break statement has appeared or the end of the switch statement is reached.

Syntax;
switch (n)
{
case label 1:
code to be executed if n=label1;
break;
case label 2:
code to be executed If n=label2;
break;
case label3:
code to be executed if n=label3;
break;
…
default:
code to be executed if n is different from all labels;
}

Example;
<?php
$favcolor = “red”;
switch ($favco!or) {
case “red”:
echo “Your favorite color is red!”;
break;
case “blue”:
echo “Your favorite color is blue!”;
break;
case “green”:
echo “Your favorite color is green!”;
break;
default:
echo “Your favorite color is neither red, blue, nor green!”;
}
?>

Question 3.
Explain the process of Conditional Statements in PHP?
Answer:
Conditional statements are useful for writing decision-making logics. It is the most important feature of many programming languages, including PHP. They are implemented by the following types:

(i) if Statement:
If statement executes a statement or a group of statements if a specific condition is satisfied as per the user expectation.

(ii) if…else Statement:
If statement executes a statement or a group of statements if a specific condition is satisfied by the user expectation. When the condition gets false (fail) the else block is executed.

(iii) if…elseif….else Statement:
If-elseif-else statement is a combination of if-else statement. More than one statement can execute the condition based on user needs.

(iv) Switch Case:
The switch statement is used to perform different actions based on different conditions.

Question 4.
Explain concepts of if elseif else statement.
Answer:

• If-elseif-else statement is a combination of if-else statement.
• More than one statement can execute the condition based on user needs.

Syntax:
if (1st condition)
{
Execute statement(s) if condition is true;
}
elseif(2nd condition)
{
Execute statement(s) if 2ndcondition is true;
}
else
{
Execute statement(s) if both conditions are false;
}

Example Program:
<?php
$Pass_Mark=35;
$first_class=60;
$Student_Mark=70;
if ($Student_Mark>= $first_class){ echo “The Student is eligible for the promotion with First Class”;
}
elseif ($Student_Mark>= $Pass_Mark){ echo “The Student is eligible for the promotion”;
}
else {
echo “The Student is not eligible for the promotion”;
}?>

Question 5.
Explain the if-else statement in PHP.
Answer:
If else statement in PHP:
If a statement executes a statement or a group of statements if a specific condition is satisfied by the user expectation. When the condition gets false (fail) the else block is executed.
Syntax:
if (condition)
{
Execute statement(s) if condition is true;
} else
{
Execute statement(s) if condition is false;
}
Example:
<?php
$Pass_Mark=35;
$Student_Mark=70;
if ($Student_Mark>= $Pass_Mark)
{
echo “The Student is eligible for the promotion”;
}
else
{
echo “The Student is not eligible for the promotion”; }
?>

12th Computer Applications Guide PHP Conditional Statements Additional Important Questions and Answers

Part A

Choose The Correct Answers:

Question 1.
How many types of PHP conditional statements are there?
(a) 2
(b) 3
(c) 4
(d) 5
Answer:
(c) 4

Question 2.
What will be the output of the following PHP code ?
<?php
if(0.0)
print”hi”;
else
print”how are u”;
?>
a) how are u
b) hi
c) error
d) no output
Answer:
a) how are u

Question 3.
The ……………………….. statement is used to perform different actions based on different conditions.
Answer:
switch

Question 4.
What will be the output of the following PHP code ?
<?php
$a=”l”;
switch($a)
{
case1:
break;
print”hi”;
case2:
print’tiello”;
break;
default:
print”hil”;
>
?>
a) hihellohi1
b) hi
c) hihi1
d) hi1
Answer:
a) hihellohi1

Question 5.
What will be the output of the following PHP code ?
<?php
$x=l;
if($x=$x&0)
print$x;
else
break;
?>
a) 0
b) 1
c) error
d) no output
Answer:
c) error

Question 6.
Which of the following can check for multiple values at a time?
(a) If
(b) If else
(c) Nested else
(d) Switch
Answer:
(d) Switch

Very Short Answers

Question 1.
How conditional statements perform?
Answer:
It performs different actions for different decisions in programing language

Question 2.
What is an “if statement” in PHP?
Answer:
The If Statement is a way to make decisions based upon the result of a condition.

Question 3.
How switch statement and if statement differs?
Answer:
Switch statements work the same as if statements but they can check for multiple values at a time

Match the following:

1. Simple if statements – Multiple branching
2. If-else statement – Combination of if-else statement
3. If elseif else statement – Only one option
4. Switch case statement – Alternative statement

Part B

Short Answers

Question 1.
Write the syntax of the If statement.
Answer:
if (condition)
{
Execute statement(s) if condition is true;
}

Question 2.
What is mean by If else ladder?
Answer:

• Else executes the following block of statements if the condition in the corresponding if is false.
• After the else, if another condition is to be checked, then an if statement follows the else. This is else if and is called as if-else ladder.

SYNTAX:

1. If statement
Answer:
if (condition)
{
Execute statement(s) if condition is true;
}

2. If else statement
if (condition)
{
Execute statement(s) if condition is true;
}
else
{
Execute statement(s) if condition is false;
}

3. If elseif else statement
if (1st condition)
{
Execute statement(s) if condition is true;
}
elseif(2nd condition)
{
Execute statement(s) if 2ndcondition is true;
}
else
{
Execute statement(s) if both conditions are false;
}

4. Switch Case:
switch (n) { case label 1:
code to be executed if n=label1;
break;
case Iabel2:
code to be executed if n=label2;
break;
case Iabel3:
code to be executed if n=label3;
break;
…
default:
code to be executed if n is different from all labels;
}

Part C

Explain in brief answer

Question 1.
Give the Syntax for If else statements in PHP?
Answer:
if (1st condition)
{
Execute statement(s) if condition is true;
}
elseif(2nd condition)
{
Execute statement(s) if 2nd condition is true;
}
else
{
Execute statement(s) if both conditions are false;
}

Programs

Question 1.
Write a php program to birthday greetings using if statement.
Answer:
<?php
$date=date(“m-d”);
if ($date==»01T0»)
{
echo “Wishing you a very Happy Birthday”;
}
?>

Question 2.
Write a php program to check whether the given number is positive or negative.
Answer:
<?php
$x = -12;
if ($x > 0)
{
echo “The number is positive”;
}
else{
echo “The number is negative”;
}
?>

Question 3.
Write a PHP program to display independence day and republic day the greetings using If elseif else statement
Answer:
<?php
$x = “August”;
if ($x == “January”) {
echo “Happy Republic Day”;
}
elseif ($x == “August”) {
echo “Happy Independence Day!!!”;
}
else{
echo “Nothing to show”;
}
?>

Part D

Explain in detail

Question 1.
Write a PHP code to display the days of weak using switch statement
Answer:
<?php
$today=date(“D”);
switch($today)
{
case”Mon”:
echo’Today is Monday.
break;
case”Tue”:
echo’Today is Tuesday.”;
break;
case”Wed”:
echo’Today is Wednesday.”;
break;
case’Thu”:echo’Today is Thursday.”;
break;
case”Fri”:
echo’Today is Friday. Party tonight.”;
break;
case”Sat”:echo’Today is Saturday.”;
break;
case”Sun”:
echo’Today is Sunday.”;
break;
default:
echo”No information available for that day.”;
break;
}
?>

Question 2.
Write a PHP program to display week days using switch case statement.
Answer:
<?php
$n = “February”;
switch($n) {
case “January”:
echo “Its January”;
break;
case “February”:
echo “Its February”;
break;
case “March”:
echo “Its March”;
break;
case “April”:
echo “Its April”;
break;
case “May”:
echo “Its May”;
break;
case “June”:
echo “Its June”;
break;
case “July”:
echo “Its July”;
break;
case “August”:
echo “Its August”;
break;
case “September”:
echo “Its September”;
break;
case “October”:
echo “Its October”;
break;
case “November”:
echo “Its November”;
break;
case “December”:
echo “Its December”;
break;
default:
echo “Doesn’t exist”;
}
?>

Tamilnadu State Board New Syllabus Samacheer Kalvi 12th Computer Applications Guide Pdf Chapter 5 PHP Function and Array Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 12th Computer Applications Solutions Chapter 5 PHP Function and Array

12th Computer Applications Guide PHP Function and Array Text Book Questions and Answers

Part I

Choose The Correct Answers

Question 1.
Which one of the following is the right way of defining a function in PHP?
a) function { function body }
b) data type functionName(parameters) { function body }
c) functionName(parameters) { function body }
d) function functionName(parameters) { function body }
Answer:
d) function functionName(parameters) { function body }

Question 2.
A function in PHP which starts with (double underscore) is known as ……………
a) Magic Function
b) Inbuilt Function
c) Default Function
d) User Defined Function
Answer:
a) Magic Function

Question 3.
PHP’s numerically indexed array begins with position …………….
a) 1
b) 2
c) 0
d) -1
Answer:
c) 0

Question 4.
Which of the following are correct ways of creating an array?
i) state[0] = “Tamilnadu”;
ii) $state[] = array(“Tamilnadu”);
iii) $state[0] = “Tamilnadu”;
iv) $state = array(“Tamilnadu”);
a) iii) and iv)
b) ii) and iii)
c) Only i)
d) ii), iii) and iv)
Answer:
d) ii), iii) and iv)

Question 5.
What will be the output of the following PHP code?
<?php
$a=a rray (“A”,”Cat”,”Dog “,”A”,”Dog “);
$b=a rray C’A” “A” “Cat”,”A”,”Tiger”);
$c=array_combine($a,$b);
print__r(array_count_va!ues($c));
?>
a) Array ([A] => 5 [Cat] = > 2 [Dog] => 2 [Tiger] = >1)
b) Array ([A] => 2 [Cat] => 2 [Dog] => 1 [Tiger] = > 1)
c) Array ( [A] => 6 [Cat] => 1 [Dog] -> 2 [Tiger] = > 1)
d) Array ([A] => 2 [Cat] => 1 [Dog] => 4 [Tiger] = > 1)
e) None of these
Answer:
e) None of these

Question 6.
For finding nonempty elements in array we use
a) is„array () function
b) sizeof () function
c) array_count () function
d) count () function
Answer:
b) sizeof () function

Question 7.
Indices of arrays can be either strings or numbers and they are denoted as
a) $my_array {4}
b) $my_array [4]
c) $my_array | 4 |
d) None of them
Answer:
d) None of them

Question 8.
PHP arrays are also called as
a) Vector arrays
b) Perl arrays
c) Hashes
d) All of them
Answer:
a) Vector arrays

Question 9.
As compared to associative arrays vector arrays are much
a) Faster
b) Slower
c) Stable
d) None of them
Answer:
b) Slower

Question 10.
What functions count elements in an array?
a) count
b) Sizeof
c) Array_Count
d) Count_array
Answer:
a) count

Part II

Short Answers

Question 1.
Define Function in PHP.
Answer:
In most of the programming language, a block of the segment in a program that performs specific operation tasks (Insert, Execute, Delete, Calculate, etc.). This segment is also known as Function. A Function is a type of subroutine or procedure in a program.

Question 2.
Define User define Function.
Answer:

• User-Defined Function (UDF) in PHP gives a privilege to the user to write their own specific: operation inside of existing program module.
• A user-defined function declaration begins with the keyword “function”.
• Users can write any custom logic inside the function block.

Question 3.
What is parameterized Function?
Answer:
Parameterized Function:

1. PHP Parameterized functions are the functions with parameters or arguments.
2. Required information can be shared between function declaration and function calling part inside the program.
3. The parameter is also called as arguments, it is like variables.
4. The arguments are mentioned after the function name and inside of the parenthesis.
5. There is no limit for sending arguments, just separate them with a comma notation.

Question 4.
List out System defined Functions.
Answer:

• is_bool() function -By using this function, we can check whether the variable is a boolean variable or not.
• is_int() function 3y using this function, we can check the input variable is an integer or not.
• is_float() function-By using this function, we can check the float variable is an integer or not.
• is_null() function-By using the is_null function, we can check whether the variable is NULL or not.

Question 5.
Write Syntax of the Function in PHP.
Answer:
SYNTAX:
function functionName()
{
Custom Logic code to be executed;
}

Question 6.
Define Array in PHP.
Answer:
Array is a concept that stores more than one value of the same data type (homogeneous) in the single array variable. They are 3 types of array in PHP.

1. Indexed Arrays
2. Associative Array and
3. Multi-Dimensional Array

Question 7.
Usage of Array in PHP.
Answer:
The array() function is used to create an array.
In PHP, there are three types of arrays:

• Indexed arrays – Arrays with a numeric index
• Associative arrays – Arrays with named keys
• Multidimensional arrays – Arrays containing one or more arrays

Question 8.
List out the types of the array in PHP.
Answer:
They are 3 types of array concepts in PHP.

1. Indexed Arrays,
2. Associative Array and
3. Multi-Dimensional Array.

Question 9.
Define associative array.
Answer:
Associative arrays are a key-value pair data structure. Instead of having storing data in a linear array, with associative arrays you can store your data in a collection and assign it a unique key which you may use for referencing your data.

Question 10.
Write array Syntax in PHP.
Answer:
array(key=>value,key=>value,key=> value,etc.); key = Specifies the key (numeric or string value – Specifies the value)

Part III

Explain in brief answer

Question 1.
Write the features System define Functions.
Answer:
System Defined Functions: A function is already created by system it is a reusable piece or block of code that performs a specific action. Functions can either return values when called or can simply perform an operation without returning any value.

Features of System defined functions:

1. System defined functions are otherwise called as predefined or built-in functions.
2. PHP has over 700 built in functions that performs different tasks.
3. Built in functions are functions that exists in PHP installation package.

Question 2.
Write the purpose of parameterized Function.
Answer:

• Information can be passed to functions through arguments.
• An argument is just like a variable.
• Arguments are specified after the function name, inside the parentheses. We can add as many arguments as you want, just separate them with a comma.

Question 3.
Differentiate user define and system define Functions.
Answer:

Question 4.
Write Short notes on Array.
Answer:
Array is a concept that stores more than one value of same data type (homogeneous) in single array variable. They are 3 types of array concepts in PHP.

1. Indexed Arrays,
2. Associative Array and
3. Multi-Dimensional Array.

Question 5.
Differentiate Associate array and Multidimensional array.
Answer:

Part IV

Explain in detail

Question 1.
Explain Function concepts in PHP.
Answer:
Functions in PHP
In most the programming language, a block of segments in a program that performs specific operation tasks (Insert, Execute, Delete, Calculate, etc.). This segment is also known as Function. A Function is a type of subroutine or procedure in a program.

Function will be executed by a call to the Function and the Function returns any data type values or NULL value to called Function in the part of the respective program.
The Function can be divided into three types as follows:

1. User-defined Function,
2. Pre-defined or System or built-in Function, and
3. Parameterized Function.

1. User-Defined Function:
User-Defined Function (UDF) in PHP gives a privilege to the user to write own specific operation inside of existing program module. Two important steps the Programmer has to create for users to define Functions are Function declaration and Function calling.

2. System Define Functions:
A function is already created by system it is a reusable piece or block of code that performs a specific action. Functions can either return values when called or can simply perform an operation without returning any value.

3. Parameterized Function:
PHP Parameterized functions are the functions with parameters or arguments.

Question 2.
Discuss in detail User-defined Functions.
Answer:

• User-Defined Function (UDF) in PHP givesa privilege to user to write own specific operation inside of existing program module.
• Two important steps the Programmer has to cre-ate for users define Functions are:

Function Declaration

• A user-defined Function declaration begins with the keyword “function”.
• User can write any custom logic inside the function block.

Syntax:
function functionName()
{
Custom Logic code to be executed;
}

Function Calling:

• A function declaration part will be executed by a ! call to the function.
• Programmer has to create Function Calling part j inside the respective program.

Syntax:
functionName();

Example:
<?php
function insertMsg() {
echo “Student Details Inserted Successfully!”;
}
insertMsg(); // call the function
?>

Question 3.
Explain the Multidimensional Array.
Answer:
Multidimensional Arrays:

1. A multidimensional array is an array containing one or more arrays.
2. PHP understands multidimensional arrays that are two, three, four, five, or more levels deep.
3. However, arrays more than three levels deep are hard to manage for most people.

Example:
<?php
// A two-dimensional array Sstudent-array
(
array(“Iniyan”, 100,96),
array(“Kavin”,60,59),
array(“Nilani”,1313,139)
);
echo $$student[0][0].“: Tamil Mark: “.$student [0][1]English mark: “.$student [0] [2].”<br>”;

echo $$student[1][0].“: Tamil Mark: “.$student [1][1].”. English mark: “.$student [1] [2].”<br>”;

echo $$student[2][0].“: Tamil Mark: “.$student [2][1]English mark: “.$student [2] [2].”<br>”;
?>

Question 4.
Explain Array concepts and their types.
Answer:
Array is a concept that stores more than one value of same data type (homogeneous) insingle array variable. They are 3 types of array con¬cepts in PHP.

1. Indexed Arrays,
2. Associative Array and
3. Multi-Dimensional Array.

Indexed Arrays

Arrays with numeric index for the available values in array variable which contains keyvalue pair as user / developer can take the values using keys.

Associative Arrays

• Associative arrays are a key-value pair data structure.
• Instead of having storing data in alinear array, with associative arrays you can store your data in a collection and assign it aunique key which you may use for referencing your data.

Multidimensional Arrays

• A multidimensional array is an array containing one or more arrays.
• PHP understands multidimensional arrays that are two, three, four, five, or more levels deep.
• However, arrays more than three levels deep are hard to manage for most people.

Question 5.
Explain Indexed array and Associatearray in PHP.
Answer:
Indexed Arrays:
Arrays with numeric index for the available values in array variable which contains key value pair as user / developer can take the values using keys.
Example:
<?php
$teacher_name=array(“Iniyan”, “Kavin”, “Nilani”);
echo “The students name are “ . $teacher_name[0]. “, “ . $$teacher_name[l]. “ and” . $teacher_name[2].
?>

Associative Arrays:

1. Associative arrays are a key-value pair data structure.
2. Instead of having storing data in a, linear array, with associative arrays you can store your data.

Example:
<?php
$Marks=array(“Student1”=>“35”,“Student2”==>“17”,“Student3”=>“43”);
echo “Student1 mark is” . $Marks[‘Student1’]. “ is eligible for qualification”;
echo “Student2 mark is” . $Marks[‘Student2’]. “ is not eligible for qualification”;

12th Computer Applications Guide Introduction to Hypertext Pre-Processor Additional Important Questions and Answers

Part A

Choose The Correct Answers:

Question 1.
A block of the segment in a program that performs specific operation tasks is known as
a) Arrays
b) Segments
c) Functions
d) All of these
Answer:
c) Functions

Question 2.
PHP has over ………………………. built-in functions.
(a) 200
(b) 500
(c) 700
(d) 900
Answer:
(c) 700

Question 3.
is a concept that stores more than one value of the same data type in a single array variable,
a) Arrays
b) Segments
c) Functions
d) All of these
Answer:
a) Arrays

Question 4.
………………….. arrays are a key-value pair data structure.
a) Associative
b) Indexed
c) Multi-dimensional
d) All of these
Answer:
b) Indexed

Question 5.
Find the wrong statement from the following?
(a) pre-defined functions are called built-in functions
(b) pre-defined functions are called system functions
(c) parameterized functions are called system functions
Answer:
(c) parameterized functions are called system functions

Fill in the blanks:

1. PHP has over …………. functions built-in that perform different tasks.
Answer:
700

2. PHP functions are dived into …………. types.
Answer:
three

3. A user-defined Function declaration begins with the keyword ………….
Answer:
function

4. The parameter is also called………….
Answer:
arguments

5. Array defines with the keyword ………….
Answer:
array()

SYNTAX

1. Function Declaration:
function functionName()
{
Custom Logic code to be executed;
}

2. Function Calling:
functionName();

3. Indexed Arrays:
$Array_Variable = array( “valuel”, “value2″”value2”);

4. Associative Arrays
array(key=>value,key=>value,key=>- value,etc.);

Choose the incorrect statements;

1. a) PHP Functions are Reducing duplication of code
b) PHP Functions are Decomposing complex problems into simpler pieces
c) PHP Functions are Improving the clarity of the code
d) PHP Functions are collections of variables.
Answer:
d) PHP Functions are collections of variables.

2. a) PHP Functions are Reuse of code
b) PHP Functions are Information hiding
c) PHP Parameterized functions are the functions without parameters
d) PHP arrays are using For each looping concepts
Answer:
c) PHP Parameterized functions are the functions without parameters

3. a) Array is a collection of heterogeneous data
b) An Array is a block of code that performs a specific action.
c) A function is already created by the system it is a reusable piece
d) An array is a special variable, which can hold more than one value at a time.
Answer:
b) An Array is a block of code that performs a specific action.

Question 4.
a) An array is a block of statements that can be used repeatedly in a program.
b) The index can be assigned automatically in a collection of the data set
c) A multidimensional array is an array containing one or more arrays.
d) Associative arrays are arrays that use named keys that you assign to them.
Answer:
a) An array is a block of statements that can be used repeatedly in a program.

5. a) User Defined Function (UDF) in PHP gives a privilege to the user to write own specific operation inside of existing program module.
b) A user-defined Function declaration begins with the keyword “function”.
c) A Function is a type of subroutine or procedure in a program.
d) A Function will not be executed by a call to the Function
Answer:
d) A Function will not be executed by a call to the Function

Match the following:

1. Indexed Arrays – System function
2. Associative Arrays – Function with arguments
3. Multidimensional Arrays – Key value pair
4. Parameterized function – Array containing one or more array
5. Predefined function – Numeric Index

Answer:
1. Numeric Index
2. Key valued pair
3. Array containing one or more array
4. Function with arguments
5. System Function

Very Short Answers

Question 1.
Classify functions?
Answer:
The Function can be divided into three types as follow:

1. User-defined Function
2. Pre-defined or System or built-in Function, and
3. Parameterized Function.

Question 2.
What is an associative array?
Answer:
Associative arrays are arrays that use named keys that you assign to them.

Question 3.
How index will be assigned in an indexed array?
Answer:
The index can be assigned automatically in a collection of the data set

Question 4.
What is a Multi-Dimensional Array?
Answer:
A multidimensional array is an array containing one or more arrays.

Part B

Short Answers

Question 1.
Write a PHP program for function with one arguments?
Answer:
<?php
function School_Name($sname) {
echo $sname.“in Tamilnadu.<br>”;
}
SchoolName (“Government Higher Secondary School Madurai”);
SchoolName (“Government Higher Secondary School Trichy”);
School Name (“Government Higher Secondary School Chennai”);
School Name (“Government Higher Secondary School Kanchipuram”);
School Name (“Government Higher Secondary School Tirunelveli”);
?>

Question 2.
Give important characteristics of PHP functions?
Answer:

1. PHP Functions are Reducing duplication of code.
2. PHP Functions are Decomposing complex problems into simpler pieces.
3. PHP Functions are Improving the clarity of the code.
4. PHP Functions are Reuse of code.
5. PHP Functions are Information hiding.

Tamilnadu State Board New Syllabus Samacheer Kalvi 11th Commerce Guide Pdf Chapter 2 Objectives of Business Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 11th Commerce Solutions Chapter 2 Objectives of Business

11th Commerce Guide Objectives of Business Text Book Back Questions and Answers

EXERCISE

I. Choose the Correct Answer

Question 1.
The Primary objective of a business is ……………………
a) Making Profit
b) Not Making Profit
c) Special skill
d) None of the above
Answer:
a) Making Profit

Question 2.
Occupation of a Doctor is ……………….
a) Employment
b) Business
c) Profession
d) Sole Proprietor
Answer:
c) Profession

Question 3.
The following does not characterize business activity?
a) Production of goods and services
b) Presence of Risk
c) Sale or exchange of goods and services
d) Salary or wages
Answer:
d) Salary or wages

Question 4.
Activities undertaken out of love and affection or with social service motive are termed as:
a) Economic activities
b) Monetary activities
c) Non Economic Activities
d) Financial Activities
Answer:
c) Non Economic Activities

II. Very Short Answer Questions

Question 1.
Define Economic Activities.
Answer:
Economic activities are those activities which are undertaken to earn money or financial gain for livelihood.

Question 2.
What do you mean by Business?
Answer:
Business refers to any human activity undertaken on a regular basis with the object to earn profit through production, distribution, sale, or purchase of goods and services.

Question 3.
Define Profession.
Answer:
Professions are those occupations which involve rendering of personal services of a special and expert nature. A profession is something which is more than a job. It is a career for someone who is competent in their respective areas.

Question 4.
What do you mean by Employment?
Answer:
The occupation through which people work for others and get remuneration in the form of wages or salaries is known as employment.
E.g. Managers, Clerks, Bank officials, Factory workers etc.

III. Short Answer Questions

Question 1.
What do you mean by human activities? Explain.
Answer:
Human activity is an activity performed by a human being to meet his/her needs and wants or maybe for personal satisfaction. Human activities can be categorized into economic and non – economic activities.

Question 2.
Write short notes on:
(a) Business
(b) Profession
Answer:
Business:
Business refers to any human activities undertaken on a regular basis with the objective to earn profit through production, distribution, purchase, and sale of goods and senders. It is connected with raising, producing, or processing goods. Business activities are classified on the basis of size, ownership, and function.

Profession:
The occupation involves the rendering of personal services of a special and expert nature. It is a career for someone who is competent in their respective areas. It includes professional activities which are subject to guidelines or codes of conduct laid down by professional bodies. The persons engaged in the profession are called professionals and they earn income by charging professional fees.

Question 3.
Explain the concept of ‘Business.
Answer:
Business refers to any human activity undertaken on a regular, basis with the object to earn profit through production, distribution, sale, or purchase of goods and services. Business activities are connected with raising, producing, or processing goods. The industry creates form utility to goods by bringing materials into the form which is useful for intermediate consumption or final consumption by consumers.

Question 4.
Briefly state the human objectives of a business.
Answer:
It refers to the objectives aimed at the well being as well as the fulfillment of expectations of employees as also of people who are disabled, handicapped, and deprived of proper education and training. It includes the economic well-being of the employees, social and psychological satisfaction of employees, and the development of human resources.

IV. Long Answer Questions

Question 1.
Explain the characteristics of Business.
Answer:
1. Production or Procurement of Goods: Goods must be produced or procured in order to satisfy human wants.

2. Sale, Transfer, or Exchange: There must be a sale or exchange of goods or services. When a person weaves cloth for his personal consumption, it is not business because there is no transfer or sale.

3. Dealing in Goods and Services: Goods produced or procured may be consumer goods like cloth, pen, brush, bag, etc., or producer-goods like plant and machinery. Services refer to activities like a supply of electricity, gas or water, transportation, banking, insurance, etc.

4. Regularity of Dealings: An isolated dealing in buying and selling does not constitute a business. The transactions must be regular.

5. Profit Motive: An important feature of the business is profit motive. Business is an economic activity by which human beings make their living.

6. Element of Risk: The profit that is expected in a business is always uncertain because it depends upon a number of factors beyond the control of the businessman.

Question 2.
Compare business with profession and employment.
Answer:

Question 3.
Discuss any five objectives of the business.
Answer:
1. Economic Objectives:
Economic objectives of business refer to the objective of earning profit and also other objectives that are necessary to be pursued to achieve the profit objective, which includes the creation of customers, regular innovations, and best possible use of available resources.

2. Social Objectives:
Social objectives are those objectives of the business, which are desired to be achieved for the benefit of society. Since business operates in society by utilizing its scarce resources, the society expects something in return for its welfare.

3. Organizational Objectives:
The organizational objectives denote those objectives an organization intends to accomplish during the course of its existence in the economy like expansion and modernization, the supply of quality goods to consumers, customers’ satisfaction, etc.

4. Human Objectives:
Human objectives refer to the objectives aimed at the well being as well as the fulfillment of expectations of employees as also of people who are disabled, handicapped, and deprived of proper education and training.

The human objectives of business may thus include the economic well-being of the employees, social and psychological satisfaction of employees, and development of human resources.

5. National Objectives:
Being an important part of the country, every business must have the objective of fulfilling national goals and aspirations.

Question 4.
Distinguish between economic and non-economic activity.
Answer:

11th Commerce Guide Objectives of Business Additional Important Questions and Answers

Question 1.
Human activities can be categorised into …………….. types.
(a) One
(b) Two
(c) Three
(d) Four
Answer:
(b) Two

Question 2.
Which of the following is not characterized as economic activities?
a) Production of goods by the manufacturer
b) Selling by retailers
c) Medical advice rendered by a physician
d) Celebrating festivals
Answer:
d) Celebrating festivals

Question 3.
Occupations may be classified into ……………. categories.
(a) One
(b) Two
(c) Three
(d) Four
Answer:
(c) Three

Question 4.
Occupation in which people work for others and get remuneration is known as ………………….
a) Profession
b) Business
c) Exchange of services
d) Employment
Answer:
d) Employment

Question 5
………………. refers to the occupation in which people work for others and get remuneration in the form of wages or salaries.
(a) Employment
(b) Profession
(c) Business
(d) Industry
Answer:
(a) Employment

Question 6.
Economic activities performed for earning profits is known as ……………
a) Business
b) Employment
c) Profession
d) Avocation
Answer:
a) Business

Question 7.
An enterprise which is owned, managed and controlled by Government and private entrepreneurs are known as ……………
a) Public Enterprise
b) Private Enterprise
c) Joint Enterprise
d) Co-operative Society
Answer:
c) Joint Enterprise

Question 8.
Which one of the following is the example for Public Enterprises?
a) State Trading Corporation (STC)
b) Ramesh Bros
c) Maruti Suzuki
d) Sole Trader Concern
Answer:
a) State Trading Corporation (STC)

Question 9.
The National Objectives of business is ……………………
a) Promote Social justice
b) Special skill
c) Making a profit
d) Satisfaction of employees
Answer:
a) Promote Social justice

Question 10.
The primary objective of a business is ……………
a) Making Profit
b) Not Making Profit
c) Special skill
d) None of the above
Answer:
a) Making Profit

Question 11.
Occupation of a Doctor is …………..
a) Employment
b) Business
c) Profession
d) Sole proprietor
Answer:
d) Sole proprietor

Question 12.
The following does not characterize business activity …………………….
a) Production of goods and services
b) Presence of Risk
c) Sale or exchange of goods and services
d) Salary or wages
Answer:
c) Sale or exchange of goods and services

Question 13.
Activities undertaken out of love and affection or with social service motive are termed as …………….
a) Economic activities
b) Monetary activities
c) Non-Economic activities
d) Financial activities
Answer:
a) Economic activities

Question 14.
The economic activity which is connected with the conversion of resources into useful goods is known as ……………..
a) Commerce
b) Trade
c) Industry
d) Business
Answer:
a) Commerce

II. Very Short Answer Questions

Question 1.
What do you mean by non-economic activities?
Answer:
Activities undertaken to satisfy social and psychological needs are called non-economic activities.

Question 2.
What do you mean by Employment?
Answer:
The occupation through which people work for others and get remuneration in the form of wages or salaries is known as employment.

Question 3.
What are Private Enterprises?
Answer:
An enterprise is said to be a private enterprise where is owned, managed, and controlled by persons other than Government.

Question 4.
What are Joint Enterprises?
Answer:
When an enterprise is owned, managed, and controlled by Government and private entrepreneurs, it is known as joint enterprises. E.g. Maruti Suzuki.

Question 5.
What is Joint Enterprise?
Answer:
An enterprise is said to be a joint enterprise where it is owned, managed, and controlled by Government and private entrepreneurs. Example – Maruti Suzuki

Question 6.
How do you explain large-scale business?
Answer:
The units which require large capital, employ a large number of workers and produce the goods on large scale is known as Large Scale business.
E.g: Suffola, Sunflower oil industries. (Extraction of edible oil from oilseeds in oil mills.)

IV. Long Answer Questions

Question 1.
Briefly explain the Business activities on the basis of Ownership.
Answer:
On the basis of ownership business activities may be broadly grouped into three categories.

D Private Enterprises:
An enterprise is said to be a private enterprise where it is owned, managed, and controlled by persons other than Government.

Sole proprietorship.
Example – Sundar Stationeries
D Partnership firms.
Example – Ramesh Bros.

Public Enterprises:
An enterprise is said to be a public enterprise where it is owned, managed, and controlled by the Government or any of its agencies or both. Public enterprises may be organized in several forms such as

• Departmental undertaking – Public Works Department (PWD)
• Public Corporation – Oil and Natural Gas Corporation (ONGC)
• Government Company – State Trading Corporation (STC)

Joint Enterprises:
An enterprise is said to be a joint enterprise where it is owned, managed, and controlled by Government and private entrepreneurs.
Example: Maruti Suzuki.

Question 2.
Write any three characteristics of Business.
Answer:
1. Production or Procurement of Goods:
Goods must be produced or procured in order to satisfy human wants.

2. Sale, Transfer, or Exchange:
There must be a sale or exchange of goods or services. When a person weaves cloth for his personal consumption, it is not business because there is no transfer or sale.

3. Dealing in Goods and Services:
Goods produced or procured may be consumer goods like cloth, pen, brush, bag, etc., or producer goods like plant and machinery. Services refer to activities like a supply of electricity, gas or water, transportation, banking, insurance, etc.

Tamilnadu State Board New Syllabus Samacheer Kalvi 12th Economics Guide Pdf Chapter 12 Introduction to Statistical Methods and Econometrics Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 12th Economics Solutions Chapter 12 Introduction to Statistical Methods and Econometrics

12th Economics Guide Introduction to Statistical Methods and Econometrics Text Book Back Questions and Answers

Part – I

Multiple Choice questions

Question 1.
The word ‘statistics’ is used as ……………..
a) Singular
b) Plural
c) Singular and Plural
d) None of above
Answer:
c) Singular and Plural

Question 2.
Who stated that statistics as a science of estimates and probabilities.
a) Horace Secrist
b) R. A Fisher
c) Ya – Lun – Chou
d) Boddington
Answer:
d) Boddington

Question 3.
Sources of secondary data are ……………..
a) Published sources
b) Unpublished sources
c) neither published nor unpublished sources
d) Both (A) and (B)
Answer:
d) Both (A) and (B)

Question 4.
The data collected by questionnaires are ………………….
a) Primary data
b) Secondary data
c) Published data
d) Grouped data
Answer:
a) Primary data

Question 5.
A measure of the strength of the linear relationship that exists between two variables is called:
a) Slope
b) Intercept
c) Correlation coefficient
d) Regression equation
Answer:
c) Correlation coefficient

Question 6.
If both variables X and Y increase or decrease simultaneously, then the coefficient of correlation will be:
a) Positive
b) Negative
c) Zero
d) one
Answer:
a) Positive

Question 7.
If the points on the scatter diagram indicate that as one variable increases the other variable tends to decrease the value of r will be :
a) Perfect positive
b) Perfect negative
c) Negative
d) Zero
Answer:
c) Negative

Question 8.
The value of the coefficient of correlation r lies between :
a) 0 and 1
b) -1 and 0
c) -1 and +1
d) -0.5 and +0.5
Answer:
c) -1 and +1

Question 9.
The term regression was used by :
a) Newton
b) Pearson
c) Spearman
d) Galton .
Answer:
d) Galton .

Question 10.
The purpose of simple linear regression analysis is to:
a) Predict one variable from another variable
b) Replace points on a scatter diagram by a straight-line
c) Measure the degree to which two variables are linearly associated
d) Obtain the expected value of the independent random variable for a given value of the dependent variable
Answer:
a) Predict one variable from another variable

Question 11.
A process by which we estimate the value of dependent variable on the basis of one or more independent variables is called:
a) Correlation
b) Regression
c) Residual
d) Slope
Answer:
b) Regression

Question 12.
If Y = 2 – 0.2 X, then the value of Y-intercept is equal to
a)-0.2
b) 2
c) 0.2 X.
d) All of the above
Answer:
b) 2

Question 13.
In the regression equation Y = β₀+ β₁ X, the Y is called
a) Independent variable
b) Dependent variable
c) Continuous variable
d) none of the above
Answer:
b) Dependent variable

Question 14.
In the regression equation X =β₀+ β₁ X, the X is called :
a) Independent variable
b) Dependent variable
c) Continuous Variable
d) none of the above
Answer:
a) Independent variable

Question 15.
Econometrics is the integration of
a) Economics and Statistics
b) Economics and Mathematics
c) Economics, Mathematics, and Statistics
d) None of the above
Answer:
c) Economics, Mathematics, and Statistics

Question 16.
Econometric is the word coined by
a) Francis Gal ton
b) RagnarFrish
c) Karl Person
d) Spearsman
Answer:
b) RagnarFrish

Question 17.
The raw materials of Econometrics are :
a) Data
b) Goods
c) Statistics
d) Mathematics
Answer:
a) Data

Question 18.
The term Uiin regression equation is
a) Residuals
b) Standard error
c) Stochastic error term
d) none
Answer:
c) Stochastic error term

Question 19.
The term Uiis introduced for the representation of
a) Omitted Variable
b) Standard error
c) Bias
d) Discrete Variable
Answer:
a) Omitted Variable

Question 20.
Econometrics is the amalgamation of
a) 3 subjects
b) 4 subjects
c) 2 subjects
d) 5 subjects
Answer:
a) 3 subjects

PART-B

Answer the following questions in one or two sentences.

Question 21.
What is Statistics?
Answer:

1. The term‘Statistics’is used in two senses: as singular and plural.
2. In singular form it simply means statistical methods.
3. Statistics when used in singular form helps in the collection, presentation, classification and interpretation of data to make it easily comprehensible.
4. In its plural form it denotes collection of numerical figures and facts.
5. In the narrow sense it has been defined as the science of counting and science of averages.

Question 22.
What are the kinds of Statistics?
Answer:

• Descriptive statistics
• Inferential statistics

Question 23.
What do you mean by Inferential Statistics?
Answer:

1. The branch of statistics concerned with using sample data to make an inference about a population of data is called Inferential Statistics.
2. It draws conclusion for the population based on the sample result.
3. It uses hypotheses, testing and predicting on the basis of the outcome.
4. It tries to understand the population beyond the sample.

Question 24.
What are the kinds of data?
Answer:
Data may be classified Based on characteristics.

1. Quantitative Data
2. Qualitative Data Based on sources:
3. Primary Data
4. Secondary Data.

Question 25.
Define Correlation.
Answer:
Correlation is a statistical device that helps to analyse the covariation of two or more variables. Sir Francis Galton, is responsible for the calculation of correlation coefficient.

Question 26.
Define Regression.
Answer:
Regression means going back and it is a mathematical measure showing the average relationship between two variables.

Question 27.
What is Econometrics?
Answer:
Origin Of Econometrics:

1. Economists tried to support their ideas with facts and figures in ancient times.
2. Irving Fisher is the first person, developed mathematical equations in the quantity theory of money with help of data.
3. Ragnar Frisch, a Norwegian economist and statistician named the integration of three subjects such that mathematics, statistical methods, and economics as Econometrics” in 1926.

PART – C

Answer the following questions in one paragraph.

Question 28.
What are the functions of Statistics?
Answer:

Functions of Statistics:

1. Statistics presents facts in a definite form.
2. It simplifies mass of figures.
3. It facilitates comparison.
4. It helps in formulating and testing.
5. It helps in prediction.
6. It helps in the formulation of suitable policies.

(I) Statistics are an aggregate of facts:
For example, numbers in a calendar pertaining to a year will not be called statistics, but to be included in statistics it should contain a series of figures with relationships for a prolonged period.

(II) Statistics are numerically enumerated, estimated and expressed.

(III) Statistical collection should be systematic with a predetermined purpose:
The purpose of the collection of statistics should be determined beforehand in order to get accurate information.

(IV) Should be capable of being used as a technique for drawing comparison:
It should be capable of drawing comparisons between two different sets of data by tools such as averages, ratios, rates, coefficients etc.

Question 29.
Find the Standard Deviation of the following data: 14, 22, 9, 15, 20, 17, 12, 11
(Answer: = 4.18)

Question 30.
State and explain the different kinds of Correlation.

1) Based on the direction of changé of variables:

• Positive correlation
• Negative correlation

2) Based upon the number of variables studied:

• Simple correlation
• Multiple correlations

3) Partial correlation
Based upon the constancy of the ratio of change between the variables:-

• Linear correlation 1
• Non-linear correlation

Question 31.
Mention the uses of Regression Analysis.
Answer:

1. Regression means going back and it is a mathematical measure showing the average relationship between two variables.
2. Both the variables may be random variables.
3. It indicates the cause and effect relationship between the variables and establishes a functional relationship.
4. Besides verification, it is used for the prediction of one value, in relation to the other given value.
5. The regression coefficient is an absolute figure. If we know the value of the independent variable, we can find the value of the dependent variable.
6. In regression, there is no such spurious regression.
7. It has wider application, as it studies linear and nonlinear relationships between the variables.
8. It is widely used for further mathematical treatment.

Question 32.
Specify the objectives of econometrics.
Answer:

1. It helps to explain the behaviour of a forthcoming period that is forecasting economic phenomena.
2. It helps to prove the old and established relationships among the variables or between the variables.
3. It helps to establish new theories and new relationships.
4. It helps to test the hypotheses and estimation of the parameter.

Question 33.
Differentiate the economic model with the econometric model.
Answer:
Economic Model:

1. Economic model is the theoretical construct that represents the complex economic process.
2. Economic model is based on mathematical modeling.
3. Economic model is focused on establishing the logical relationships between the variables in the model.
4. Economic model is applied in stating the theoretical relationship into mathematical equations.
5. Economic model believes that the outcome is certain and exact. So disturbance term is not required.
6. Economic model is deterministic in nature.
7. The Keynesian consumption function: C = a + by is the economic model

Econometric Model:

1. Econometric model is the statistical concept that represents the numerical estimate of the variables involved in economic process.
2. Econometric model is based on statistical modeling.
3. Econometric model is focused on estimating the magnitude and direction of relationship between the variables.
4. Econometric model is applied in stating the empirical extent of the economic model.
5. Econometric model believes that outcome is certain but not exact. So disturbance term plays the vital role.
6. Econometric model is stochastic in nature.
7. The Keynesian consumption function: C = a + by + µ is the econometric model

Question 34.
Discuss the important statistical organizations (offices) in India.
Answer:

• The Ministry of statistics has two wings, statistics and programme Implementation.
  The statistics wing called the National Statistical office (NSO) consists of the central Statistical office ((SO), the computer center and the National Sample Survey office (NSSO).
• There is also National Statistical commission created through a Resolution of Government of India and an autonomous Institute (ie) Indian Statistical Institute.

Question 35.
Elucidate the nature and scope of Statistics.
Answer:
Nature of Statistics:

1. Different Statisticians and Economists differ in views about the nature of statistics, some call it a science and some say it is an art.
2. Tippett on the other hand considers Statistics both as a science as well as an art.

Scope of Statistics:
Statistics is applied in every sphere of human activity – social as well as physical – like Biology, Commerce, Education, Planning, Business Management, Information Technology, etc.

Statistics and Economics:

1. Statistical data and techniques are immensely useful in solving many economic problems
2. Such as fluctuation in wages, prices, production, distribution of income and wealth and so on.

Statistics and Firms:
Statistics is widely used in many firms to find whether the product is conforming to specifications or not.

Statistics and Commerce:

1. Statistics are the lifeblood of successful commerce.
2. Market survey plays an important role to exhibit the present conditions and to forecast the likely changes in future.

Statistics and Education:

1. Statistics is necessary for the formulation of policies to start new courses, according to the changing environment.
2. There are many educational institutions owned by public and privately engaged in research and development work to test the past knowledge and evolve new knowledge.
3. These are possible only through statistics.

Statistics and Planning:
1. Statistics is indispensable in planning. In the modem world, which can be termed as the “world of planning”, almost all the organisations in the government are seeking the help of planning for efficient working, for the formulation of policy decisions and execution of the same.

2. In order to achieve the above goals, various advanced statistical techniques are used for processing, analyzing and interpreting data.

3. In India, statistics play an important role in planning, both at the central and state government levels, but the quality of data highly unscientific.

Statistics and Medicine:

1. In Medical Sciences, statistical tools are widely used. In order to test the efficiency of a new drug or to compare the efficiency of two drugs or two medicines, a t-test for the two samples is used.
2. More and more applications of statistics are at present used in clinical investigation.

Statistics and Modern applications:

1. Recent developments in the fields of computer and information technology have enabled statistics to integrate their models and thus make statistics a part of the decision-making procedures of many organisations.
2. There are many software packages available for solving simulation problems.

Question 36.
Calculate the Karl Pearson Correlation Co-efficient for the following data

Answer : r = 0.9955

Question 37.
Find the regression equation Y on X and X on Y for the following data:

(Answer : Y = 0.787X + 7.26, and X = 0.87Y + 26.65)

Question 38.
Describe the application of Econometrics in Economics.
Answer:

1. To forecast macroeconomics indicators:
   Econometrical methods are used to forecast macroeconomic indicators, Time – series models can be used to make predictions about economic indicators.
2. To Support Mathematical Economic Model:
   Tinbergen points out that “Econometrics as a result of certain outlook on the role of economics, consists of the application of mathematical statistics to economic data to lend empirical support to the models constructed by mathematical economics and to obtain numerical results.’
3. Econometric methods are used for the firms in a number of ways like to determine minimum wage rate, factors responsible for the firm to remain in the market, Market Functions etc.

12th Economics Guide Introduction to Statistical Methods and Econometrics Additional Important Questions and Answers

I. Match the following:

Question 1.
a) Contribution to vital statistics – 1) Kautilya
b) Father of statistics – 2) GP Nelson
c) Arthashastra – 3) Akbar’s rule
d) ‘Am – .e – Akbari – 4) Ronald Fisher

Answer:
c) 3 4 1 2

Question 2.
a) Quantitative Data – 1) Collected for the first time
b) Qualitative Data – 2) Data from NSSO
c) Primary Data – 3) Number of firms
d) Secondary Data – 4) Gender

Answer:
c) 3 4 1 2

II. Choose the correct pair

Question 1.
a) Mean – Special Average
b) Geometric Mean – Simple Average
c) Standard Deviation – Root mean square deviation
d) Dispersion – frequency deviation
Answer :
c) Standard Deviation – Root mean square Deviation

Question 2.
a) Correlation – Irving Fisher
b) Regression – Karl Pearson
c) Quantity theory – Francis Dalton
d) Econometrics – Ragnar Frisch
Answer:
d) Econometrics – Ragnar Frisch

III. Choose the incorrect pair

Question 1.
a) Statistics Day – June 29
b) NSSO – 1960
c) P. C. Mahalanobis – father of statistics in India.
d) Central Statistical office – New Delhi
Answer :
b) NSSO -1960

Question 2.
a) Positive correlation – Y = a – bx
b) Simple correlation – Y = a + bx
c) Non linear correlation – Y = a + bx²
d) Multiple correlation – Qd = f (p, P_c,P_s, t, y)
Answer:
a) Positive correlation – Y = a – bx

IV. Pick the odd one out

Question 1.
a) Scatter diagram method
b) Graphic Method
c) Karl Pearson’s coefficient of regression
d) Method of least squares
Answer:
c) Karl Pearson’s coefficient of regression

Question 2.
a) Simple correlation
b) Multiple correlations
c) Partial correlation
d) Positive correlation
Answer:
d) Positive correlation

V. Choose the correct statement

Question 1.
a) Correlation means “stepping back towards the Average”
b) Universal law of regression was given by Karl Pearson
c) Econometrics is concerned with the empirical determination of economic laws.
d) Econometrics is the integration of economics and mathematics.
Answer:
c) Econometrics is concerned with the empirical determination of economic laws

Question 2.
a) Mathematics is a science of estimates and probabilities.
b) Tipett considered statistics as a science.
c) Karl Pearson introduced the concept of standard deviation
d) Correlation is a statistical device that helps to analyse the covariation of two or more variables.
Answer:
d) Correlation is a statistical device that helps to analyse the covariation of two or more variables.

VI. Choose the incorrect statement

Question 1.
a) Sir Francis Galton, is responsible for the calculation of the correlation coefficient.
b) If three variables are taken for study it is called a simple correlation.
c) Indian statistical institute is declared as an Institute of National importance by as Act of parliament.
d) The ministry of statistics and programme Implementation came into existence in 1999
Answer:
b) If three variables are taken for study it is called a simple correlation.

Question 2.
a) Econometrics may be considered as the integration of economics, statistics
and Accountancy
b) Ragnar Frish was awarded the Nobel prize in 1969.
c) The coefficient of correlation is a relative measure.
d) Regression is used for the further mathematical treatment of the variables.
Answer:
a) Econometrics may be considered as the integration of economics, statistics, and Accountancy.

VII. Fill in the blanks.

Question 1.
The term statistics originated in the Latin word known as ………………………….
(a) Statistik
(b) Status
(c) Statistique
(d) Statistics
Answer:
(b) Status

Question 2.
“Statistics is a science of estimates and probabilities” is a statement of …………………
a) Ronald Fisher
b) Boddington
c) Croxton
d) Cowdeg
Answer:
b) Boddington

Question 3.
The first book to have statistics as its title was ………………………….
(a) Contributions to vital statistics
(b) Principles of statistics
(c) Statistics principles
(d) Statistics probabilities
Answer:
(a) Contributions to vital statistics

Question 4.
To test the efficiency of a new drug or to compare the efficiency of two drugs ………….. test in used.
a) t-test
b) f-test
c) chi-test
d) None
Answer:
a) t-test

Question 5.
The branch of statistics devoted to the summarization and description of data is called …………….. statistics.
a) Interential
b) Descriptive
c) hypothetical
d) None
Answer:
b) Descriptive

Question 6.
Who is the father of statistics?
(a) Gottfried Achenwall
(b) Francis GP. Nelson
(c) Ronald Fisher
(d) R.A. Fisher
Answer:
(d) R.A. Fisher

Question 7.
Karl Pearson introduced the concept of standard deviation is ………………….
a) 1891
b) 1892
c) 1893
d) 1894
Answer :
c) 1893

Question 8.
Statistics are the lifeblood of success………………………….
(a) Maths
(b) Datas
(c) Calculations
(d) Commerce
Answer:
(d) Commerce

VIII. Answer the following in one or two sentences.

Question 1.
Write five averages?
Answer:

1. There are five averages.
2. Among them mean, median, and mode are called simple averages and the other two averages geometric mean and harmonic mean are called special averages.

Question 2.
What is partial correlation?
Answer:
If there are more than two variables but only two variables are considered keeping the other variables constant, then the correction is said to be a partial correlation.

Question 3.
Write the kinds of dispersion?
Answer:
There are two kinds of measures of dispersion, namely

1. The absolute measure of dispersion
2. A relative measure of dispersion

Question 4.
Mention the methods of studying the correlation.
Answer:

1. Scatter diagram method.
2. Graphic method.
3. Karl person’s coefficient of correlation
4. Method of least squares.

Question 5.
State the formula to compute Karl person co-efficient of correlation.
Answer:

Question 6.
Explain the advantages of the Scatter diagram method?
Answer:
Advantages of the Scatter Diagram method:

1. It is a very simple and non-mathematical method
2. It is not influenced by the size of an extreme item.
3. It is the first step in resting the relationship between two variables.

Question 7.
What are the types of Averages?
Answer:
There are five averages. Mean, median, and mode are called simple averages and geometric mean and harmonic mean are called special averages.

IX. Answer the following question in paragraph

Question 1.
Differentiate Descriptive and Inferential statistics.
Answer:

Question 2.
Briefly explain the kinds of measures of dispersion?
Answer:
There are two kinds of measures of dispersion, namely

1. The absolute measure of dispersion
2. A relative measure of dispersion

The absolute measure of dispersion indicates the amount of variation in a set of values in terms of units of observations. Relative measures of dispersion are free from the units of measurements of the observations. They are pure numbers. They are used to compare the variation in two or more sets, which are having different units of measurements of observations. Standard Deviation is one of the methods of Absolute measure of dispersion.

Karl Pearson introduced the concept of standard deviation in 1893. Standard deviation is also called Root- Mean Square Deviation. The reason is that it is the square – root of the mean of the squared deviation from the arithmetic mean. It provides accurate results. The Square of standard deviation is called Variance.

Question 3.
Explain the Characteristics of statistics.
Answer:

• Statistics are an aggregate of facts.
• Statistics are numerically enumerated, estimated, and expressed.
• The statistical collection should be systematic with a predetermined purpose.
• Should be capable of being used as a technique for drawing a comparison.

Question 4.
What are the limitations of statistics?
Answer:

1. Statistics is not suitable to the study of the qualitative phenomenon
2. Statistical laws are not exact.
3. The statistics table may be misused.
4. Statistics is only one of the methods of studying a problem.

Question 5.
Write a short note on NSSO.
Answer:
The National sample survey organization, now known as the National sample survey office, is an organization under the ministry of statistics of the Government of India. It is the largest organization in India, conducting regular socio-economic surveys. It was established in 1950.
NSSO has four divisions:

• Survey Design and Research Division (SDRD)
•  Field Operations Division (FOD)
• Data processing division (DPD)
• Co-ordination and Publication Division (CPD)

Question 6.
Calculate the standard deviation from the following data by the Actual Mean method.
Answer:

Question 6.
Write the assumptions of the Linear Regression Model?
Answer:
Assumptions of the Linear Regression Model:
The Linear regression model is based on certain assumptions

1. Some of them refer to the distribution of the random variable.
2. Some of them refer to the relationship between U_i and the explanatory variables (x₁, x₂, x₃ given in the above example).
3. Some of them refer to the relationship between U_i the explanatory variables themselves.

X. Answer the following questions

Question 1.
Distinguish between correlation and Regression.
Answer:

Question 2.
Explain the difference between correlation and regression?
Answer:
Difference between Correlation and Regression:
Correlation:

1. Correlation is the relationship between two or more variables, which vary with the other in the same or the opposite direction.
2. Both the variables X and Y are random variables.
3. It finds out the degree of relationship between two variables and not the cause and effect relationship.
4. It is used for testing and verifying the relation between two variables and gives limited information.
5. The coefficient of correlation is a relative measure. The range of relationships lies between -1 and +1.
6. There may be a spurious correlation between the two variables.
7. It has limited application because it is confined only to a linear relationship between the variables.
8. It is not very useful for further mathematical treatment.

Regression:

1. Regression means going back and it is a mathematical measure showing the average relationship between two variables.
2. Both the variables may be random variables.
3. It indicates the cause and effect relationship between the variables and establishes the functional relationship.
4. Besides verification, it is used for the prediction of one value, in relation to the other given value.
5. The regression coefficient is an absolute figure. If we know the value of the independent variable, we can find the value of the dependent variable.
6. In regression, there is no such spurious regression.
7. It has wider application, as it studies the linear and nonlinear relationships between the variables.
8. It is widely used for further mathematical treatment.

Question 3.
Find the coefficient of correlation with the actual mean Method for the following data:

Answer:

Tamilnadu State Board New Syllabus Samacheer Kalvi 12th Computer Applications Guide Pdf Chapter 4 Introduction to Hypertext Pre-Processor Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 12th Computer Applications Solutions Chapter 4 Introduction to Hypertext Pre-Processor

12th Computer Applications Guide Introduction to Hypertext Pre-Processor Text Book Questions and Answers

Part I

Choose The Correct Answers

Question 1.
What does PHP stand for?
a) Personal Home Page
b) Hypertext Preprocessor
c) Pretext Hypertext Processor
d) Pre-processor Home Page
Answer:
b) Hypertext Preprocessor

Question 2.
What does PHP files have a default file extension?
a) .html
b) .xml
c) .php
d) .ph
Answer:
c) .php

Question 3.
A PHP script should start with………….. and end with …………….
a) <php>
b) < ? php ?>
c) < ? ? >
d) < ?php ? >
Answer:
b) < ? php ?>

Question 4.
Which of the following must be installed on your computer so as to run PHP script?
a) Adobe
b) windows
c) Apache
d) IIS
Answer:
c) Apache

Question 5.
We can use to ………… comment a single line?
i) /?
ii) //
iii) #
iv) /* */
a) Only (ii)
b) (i), (iii) and (iv)
c) (ii), (iii) and (iv)
d) Both (ii) and (iv)
e) Both (ii) and (iii)
Answer:
e) Both (ii) and (iii)

Question 6.
Which of the following PHP statement/statements will store 41 in variable num?
(i) $x = 41;
(ii) $x = ’41’;
(iii) (i) $x = “41”;
a) Both (i) and (ii)
b) All of the mentioned,
c) Only (iii)
d) Only (i)
Answer:
d) Only (i)

Question 7.
What will be the output of the following PHP code?
<?php
$num = 1;
$num1 = 2;
print $num . “+‘ $numl ;
a) 3
b) 1+2
c) 1.+.2
d) Error
Answer:
c) 1.+.2

Question 8.
Which of the following PHP statements will output Hello World on the screen?
a) echo (“Hello World”);
b) print (“Hello
World”);
c) printf (“Hello World”);
d) sprintf (“Hello
World”);
Answer:
a) echo (“Hello World”);

Question 9.
Which statement will output $x on the screen?
a) echo “\$x”;
b) echo “$$x”;
c) echo “/$x”;
d) echo “$x;
Answer:
b) echo “$$x”;

Question 10.
Which of the below symbols is a newline character?
a) \r
b) \n
c) /n
d) /r
Answer:
a) \r

Part II

Short Answers

Question 1.
What are the common usages of PHP?
Answer:

• It is a very simple and lightweight open-source server-side scripting language.
• It can easily embed with HTML and other client-side scripting languages like CSS (Cascading Style Sheets) and Javascript.
• It also creates dynamic and interactive Webpages in the red time Web development projects.

Question 2.
What is a Web server?
Answer:

• A Web sewer is Software that uses HTTP (Hypertext Transfer Protocol) to serve the files that form Web pages to users
• Web server software that runs on server hardware, governs the server-side scripting compilation into an intermediate bytecode that is then interpreted by the runtime engine,

Question 3.
What are the types of a scripting language?
Answer:
Web scripting languages are classified into two types, client-side and server-side scripting language. PHP is completely different from Client-side scripting language like Javascript. The PHP code entirely executes on Webserver which is installed in the remote machine.

Question 4.
Differentiate between Client and Server?
Answer:

Question 5.
Give few examples of Web Browser?
Answer:

• Internet Explorer
• UC Browser
• Opera
• Google Chrome and
• Mozilla Firefox.

Question 6.
What is a URL?
Answer:

• URL is the abbreviation of Uniform Resource Locator
• It is the address of a specific Web page or fiie on the Internet,
• URL is made up four parts-protocols, hostname, folder name and fiie name,
• Example: http://www.googie.com/

Question 7.
Is PHP a case sensitive language?
Answer:
Yes, smaller case & uppercase letters are different in PHP.

Examples
If you defined a variable in lowercase, then you need to use it in lowercase everywhere In the program.

Question 8.
How to declare variables in PHP?
Answer:

• Variable name must always begin with a $ symbol.
• Variable name can never start with a number,
• Variable names are case-sensitive.

Question 9.
Define Client-Server Architecture.
Answer:
The client-server architecture introduces an application sharing mechanism between two different hardware systems over the network (Internet/intranet).

Question 10.
Define Web server.
Answer:
A Web server is Software that uses HTTP (Hyper-text Transfer Protocol) to serve the files that form
Web pages to users.

Part III

Explain in brief answer

Question 1.
Write the features of server side scripting language.
Answer:

• Server-side scripting offers greater protection for user privacy
• It often reduces the loading rime for web pages
• Some browsers don’t fully support JavaScript, so server-side scripting is essential to run dynamic pages on these browsers.

Question 2.
Write is the purpose of Web servers?
Answer:

1. Webserver is software which is running in server hardware.
2. It takes the responsibilities for the compilation and execution of server-side scripting languages.
3. After receiving the request from the client machine the Web server tries to compile and interpret the PHP code which is available in remote machine.
4. Next a response will be generated and sent back to the client machine over the network from Webserver.

Question 3.
Differentiate Server side and Client Side Scripting language.
Answer:

Question 4.
In how many ways you can embed PHP code in an HTML page?
Answer:

1. PHP script can be written inside of HTML code and save the file with an extension of .php. The embedded PHP file gets executed in the Webserver, the browser receives only the HTML and other client-side files.
2. Php files can also be embedded with css and js files.
3. Using template engines like Smarty, DWOO, Mustache, Blade we can embed PHP files.

Question 5.
Write short notes on PHP operator.
Answer:
An operator is a symbol which is used to perform mathematical and logical operations in programming languages.
Different types of the operator in PHP are:

1. Arithmetic operators
2. Assignment operators
3. Comparison operators
4. Increment/Decrement operators
5. Logical operators and
6. String operators

Part IV

Explain In Detail

Question 1.
Explain client-side and server-side scripting language.
Answer:
Web scripting languages are classified into two types, client-side and server-side scripting language.
Client-side Environment

• The client-side environment used to run scripts is usually a browser.
• The processing takes place on the end-users computer.
• The source code is transferred from the webserver to the user’s computer over the internet and run directly in the browser,
• The scripting language needs to be enabled on the client computer. Sometimes if a user is conscious of security risks they may switch the scripting facility off. .
• When this is the case a message usually pops up to alert the user when the script Is attempting to run.

Server-side Environment

• A server is a computer system that serves as a central repository of data and programs and is shared by clients
• The server-side environment that runs a scripting language is a web server.
• A user’s request is fulfilled by running a script directly on the webserver to generate dynamic HTML pages.
• This HTML is then sent to the client browser.
• It is usually used to provide interactive websites that interface to databases or other data stores on the server.
• This is different from client-side scripting where scripts are run by the viewing web browser, usually in JavaScript.
• The primary advantage to server-side scripting is the ability to highly customize the response based on the user’s requirements, access rights, or queries into data stores.

Question 2.
Discuss in detail Website develop¬ment activities.
Answer:
The process of development also includes Web content generation, Web page designing, Website security, and so on.
PHP Script:

1. Website or Web page is developed by the programmer using PHP script. Finally, the entire Website codes are moved to the Web server path in a remote server machine.
2. From the client-side, the end-user opens a browser, types the URL of the Website or Webpage, and initiates the request to the remote server machine over the network.
3. After receiving the request from the client machine the Web server tries to compile and interpret the PHP code which is available in a remote machine.
4. Next, a response will be generated and sent back to the client machine over the network from Webserver.
5. Finally, the browser which is installed in the client machine receives the response and displays the output to the user.

Question 3.
Explain the process of Webserver installation.
Answer:
The following are the steps to install and config¬ure Apache Httpd Web server and PHP module in windows server machine.
Step 1:
Go to the Apache foundation Website and download the Httpd Web server Software.
https://httpd.apache.org/download.cgi

Step 2:

• After downloading. MSI file from Apache foundation Website, the user launches the. MSI file and clicks next and next button to finish the installation on the server machine.
• The software takes default port number 130 or 130130.
• Once the user finished, the Web server software is installed and configured on the server hardware machine as a service.

Step 3:

• To test the installation of the Apache Http Web server, enter the following URL from your Web browser which is installed in your client machine.
  https://iocalhost:130/ or https:// localhost:130130
• The output page that says “Its works”

Step 4:

• Administrator user can start, stop and restart the Web server service at any time via the Windows Control panel.
• Once the services stops, the client machine will not receive the response message from server machine.

Step 5:

• Webserver’s configuration setting file “httpd. conf ” is located in the conf directory under the apache installation directory.
• Edit this file and enable the PHP module to run PHP scripting language.

Question 4.
Discuss in detail PHP data types.
Answer:
PHP scripting language supports 13 primitive data types.
Data Types plays important role in all programming languages to classify the data according to the logic.
PHP supports the following data types.

1. String
2. Integer
3. Float
4. Boolean
5. Array
6. Object
7. NULL
8. Resource

Question 5.
Explain operators in PHP with examples.
Answer:
The operator is a symbol that is used to perform mathematical and logical operations in programming languages,
Different types of the operator in PHP are:

1. Arithmetic operators,
2. Assignment operators,
3. Comparison operators,
4. Increment/Decrement operators,
5. Logical operators, and
6. String operators,
7. Arithmetic operators

The Arithmetic operators in PHP perform genera! arithmetical operations, such as addition, subtraction, multiplication and division etc

Assignment Operators:

• Assignment operators are performed with numeric values to store a value to a variable.
• The default assignment operator is This operator sets the left side operant value of expression to right side variable.

Comparison Operators:

• Comparison operators perform an action to compare two values.
• These values may contain integer or string data types (Numbers or Strings).

Increment and Decrement Operators:

• Increment and decrement operators are used to perform the task of increasing or decreasing the variable’s value.
• This operator is mostly used during iterations in the program logics.

Logical Operators:
Logical Operators are used to combine conditional statements.

String Operators:
Two operators are used to perform string related operations such as Concatenation and Concatenation assignment (Appends).

12th Computer Applications Guide Introduction to Hypertext Pre-Processor Additional Important Questions and Answers

Part A

Choose The Correct Answers:

Question 1.
The variable in PHP begins with a dollar ………… symbol.
a) @
b) #
c) $
d) %
Answer:
c) $

Question 2.
……………………… Scripting languages was introduced to support Internet online business.
(a) Server
(b) Client
(c) Web
(d) Online
Answer:
(c) Web

Question 3.
In PHP, a Variable name can never start with a ………….
a) alphabet
b) number
c) both a and b
d) either a or b
Answer:
b) number

Question 4.
PHP scripting language supports …………. primitive data types.
a) 10
b) 11
c) 12
d) 13
Answer:
d) 13

Question 5.
CSS means
(a) combined script style
(b) cascading style sheets
(c) calculated spreadsheet
(d) consecutive script sheets
Answer:
(b) cascading style sheets

Question 6.
PHP was invented in ………….
a) 1992
b) 1993
c) 1994
d) 1995
Answer:
c) 1994

Question 7.
PHP can embed with ………….
a) HTML
b) CSS
c) Javascript
d) All of the above
Answer:
d) All of the above

Question 8.
JSP means
(a) Joint Server photographs
(b) Java Server pages
(c) Java Script program
(d) Active script pages
Answer:
(b) Java Server pages

Question 9.
PHP also creates ………… Webpages in thereat time Web development projects,
a) Dynamic
b) interactive
c) both a and b
d) None of these
Answer:
c) both a and b

Question 10.
78.9 % of Website are developed by ………… scripting language.
a) ASP
b) JSP
c) VbScript
d) PHP
Answer:
d) PHP

Question 11.
Which of the following is an assignment operator?
a) =
b) = =
c) = = =
d) ! = =
Answer:
a) =

Question 12.
CGI stands for
(a) Common Gateway Interface
(b) Call Gateway Interrupt
(c) Cold Gateway Interface
(d) Client Gateway Interface
Answer:
(a) Common Gateway Interface

Question 13.
Which of the following is a non-identical operator?
a) =
b) = =
c) = = =
d) ! = =
Answer:
d) ! = =

Question 14.
Which of the following is an equal operator?
a) =
b) = =
c) = = =
d) ! = =
Answer:
b) = =

Question 15.
Find the Correct one
(i) PHP is an open source
(ii) Apache tom cat supports PHP
(iii) MS-ITS Supports PHP
(a) Only (i) is true
(b) (ii), (iii) – True
(c) (i), (ii) – True
(d) (i), (ii), (iii) – True
Answer:
(d) (i), (ii), (iii) – True

Question 16.
………….is a collection of characters within the double or single quotes
a) String
b) Boolean
c) Integer
d) Float
Answer:
a) String

Question 17.
Boolean is a data type which denotes …………
a) Integer numbers
b) Decimal point numbers
c) True or False state
d) Array
Answer:
c) True or False state

Question 18.
…………is a data type which has multiple values in a single variable.
a) Integer numbers
b) Decimal point numbers
c) True or False state
d) Array
Answer:
d) Array

Question 19.
How many client-server architecture models there?
(a) 2
(b) 3
(c) 4
(d) 5
Answer:
(b) 3

Question 20.
………… is a data type which contains information about data and function inside the class.
a) Integer numbers
b) Array
c) True or False state
d) Array
Answer:
d) Array

Abbreviations:

• ASP – Active Server Page
• JSP – Java Server page
• CSS – CascadingStyle Sheets
• PHP – Hypertext Pre-processor
• WWW – World Wide Web
• CGI – Common Gatewaylnterface
• OOPs – Object-Oriented Programming

Choose the incorrect sentences:

1. a) 25% of Websites are developed by PHP scripting language.
b) PHP is a Case Sensitive
c) PHP is a Simplicity Program language
d) PHP is an Open Source
Answer:
b) PHP is a Case Sensitive

2. a) PHP is an Efficiency Program language
b) PHP is a Platform dependent Program language
c) PHP is a Security Program language
d) PHP is a Flexibility Program language
Answer:
b) PHP ¡s a Platform dependent Program language

3. a) PHP is a Real-Time Access Monitoring Program
language
b) PHP Script should with “<Tag name>” and closes with “</Tagname>’
c) PHP files have a default file extension is .php.
d) PHP stands for Personal Home Page
Answer:
b) PHP Script should with “<Tag name>” and closes with “</Tagname>’

4. a) PHP can be executed via an interpreter which is installed in the Web servers or CGI.
b) PHP is an open-source community development initiation.
c) Website or Web page is developed by the programmer using PHP script only.
d) Three types of PHP Syntax are available.
Answer:
c) Website or Web page is developed by the programmer using PHP script only.

5. a) PHP script can be written inside of HTML code and save the file with an extension of .php.
b) The embedded PHP file gets executed in the Web server.
c) The browser receives only the HTML and other client-side files.
d) The raw PHP code ¡s visible ¡n browser which means that Compiler
Answer:
d) The raw PHP code ¡s visible ¡n browser which means that Compiler

Find the odd one on the following

1. a) Python
b) C++
c) PHP
d) C
Answer:
a) Python

2. a) Microsoft SQL Server
b) Apache
c) Tomcat
d) Microsoft IIS
Answer:
a) Microsoft SQL Server

3. a) Default Syntax
b) Short open Tags
c) HTML Script embed Tags
d) Open Source
Answer:
d) Open Source

4. a) Array
b) Object
c) Structure
d) NULL
Answer:
d) NULL

5. a) Integer
b) Octal
c) Boolean
d) Float
Answer:
b) Octal

6. a) String
b) Binary
c) Resource
d) Boolean
Answer:
b) Binary

7. a) Arithmetic operators
b) Assignment operators
c) Comparison operators
d) Conditional Operator
Answer:
d) Conditional Operator

8. a) Increment operators
b) Decrement operators
c) Bitwise operator
d) Logical operators
Answer:
c) Bitwise operator

9. a) Ternary Operator
b) String operators.
c) Arithmetic Operator
d) Decrement Operator
Answer:
a) Ternary Operator

10. a) Average
b) Multiplication
c) Addition
d) Modulus
Answer:
a) Average

11. a) XOR
b) XNOR
c) AND
d) OR
Answer:
b) XNOR

12. a) =
b) = =
c) = = =
d) !=
Answer:
a) =

13. a) ! =
b) != –
c) < >
d)()
Answer:
d)()

14. a) &&
b) ||
c) !!
d) !
Answer:
c) !!

15. a) +
b) –
c) x
d) /
Answer:
c) x

Match the following:

1. String – Structured Information
2. Integer – Data and Function
3. Float – Database Connection
4. Boolean – Single value
5. Array – True/False
6. Object – Multiple values
7. NULL – Decimal numbers
8. Resource – Non- Decimal numbers
9. Var_dump() – Remainder
10. Modulus – Collection of characters
Answer:
1. Collection of characters
2. Decimal numbers
3. No-Decimal number
4. True/False
5. Multiple values
6. Data and functions
7. Single value
8. Database Connection
9. Structured information
10. Remainder

Assertion and Reason

Question 1.
Assertion (A): The Web-based Internet application ensures the success of critical business in real-world competitions.
Reason (R): The legacy programming languages meet the expectations of the latest Internet concepts and executions.
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) is false
d) (A) is false and (R) is true
Answer:
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)

Question 2.
Assertion (A): The Web-based Internet application ensures the success of critical business in real-world competitions.
Reason (R): The legacy programming languages meet the expectations of the latest Internet concepts and executions.
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) is false
d) (A) is false and (R) is true
Answer:
c) (A) is true and (R) is false

Question 3.
Assertion (A): PHP is a competitor and alternative for other server-side scripting languages like HTML and CSS.
Reason (R): Recent statistics of server-side scripting language usage depict that 78.9 % of Websites are developed by PHP scripting language.
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) is false
d) (A) is false and (R) is true
Answer:
d) (A) is false and (R) is true

Question 4.
Assertion (A): in the evolution of network architecture, various critical networks related problems are getting resolved by the client-server architecture model.
Reason (R): The client-server architecture introduces an application sharing mechanism between two different hardware systems over the network (Internet/intranet).
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) is false
d) (A) is false and (R) is true
Answer:
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)

Question 5.
Assertion (A): HTTP means HyperText Transfer Protocol. HTTP is the underlying protocol used by the World Wide Web
Reason (R); This protocol defines how messages are formatted and transmitted, and what actions Web servers and browsers should take in response to various commands
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) is false
d) (A) is false and (R) is true
Answer:
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)

Part B

Short Answers

Question 1.
Define Web browser?
Answer:

• Web Browser: A Web browser (commonly referred to as a browser) is a software application for accessing information on the World Wide Web.
• Each individual Web page, image, and video is identified by a distinct URL, enabling browsers to retrieve and display them on the user’s device.

Question 2.
Classification of Client-Server Architecture Model.
Answer:
Client-server architecture is classified into three types, as follows

• Single Tier Architecture
• Two-Tier Architecture
• N/Multi/Three tire architecture.

Question 3.
Write a note on HTTP?
Answer:
HTTP:

1. HTTP HyperText Transfer Protocol.
2. HTTP is the underlying protocol used by the World Wide Web.
3. This protocol defines how messages are formatted and transmitted.
4. The actions were taken by web servers and browsers in response to various commands.

Question 4.
Write a note on the var-dump function?
Answer:
Var_dump:

1. The var_dump( ) function is used to dump information about a variable.
2. This function displays structured information such as the type and value of the given variable.
3. Arrays and objects are explored recursively with values intended to show structure.

Part C

Explain in brief answer

Question 1.
Explain important features of PHP?
Answer:

1. PHP is an Open Source
2. PHP is a Case Sensitive
3. PHP is a Simplicity Program language
4. PHP is an Efficiency Program language
5. PHP is a Platform Independent Program language
6. PHP is a Security Program language
7. PHP is a Flexibility Program language
8. PHP is a Real-Time Access Monitoring Program language

Question 2.
Write a short note on Var_dump() function with Example.
Answer:

• The var_dump() function is used to dump information about a variable.
• This function displays structured information such as the type and value of the given variable.
• Arrays and objects are explored recursively with values intended to show structure.

Example;
<?php
$x = “COMPUTER APPLICATION!”;
$x = null; var_dump($x);
?>
OUTPUT; NULL

Question 3.
What do you mean by Resources?
Answer:

• The resource is a specific variable.
• It has a reference to an external resource.
• These variables hold specific handlers to handle files and database connections irrespective PHP program.

Part D

Explain in Detail

Question 1.
What are the three types of syntax in PHP? Explain them in detail.
Answer:
Default Syntax;
The default Syntax begins with “<?php”and closes with”?>”

Short open Tags

• The Short open Tags begins with “<?” and closes with”?>”
• But admin user has to enable Short style tags settings in the php.ini file on the server.

HTML Script embed Tags:
HTML Script embed Tags look just like HTML script tags.

Tamilnadu State Board New Syllabus Samacheer Kalvi 12th Computer Applications Guide Pdf Chapter 3 Introduction to Database Management System Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 12th Computer Applications Solutions Chapter 3 Introduction to Database Management System

12th Computer Applications Guide Introduction to Database Management System Text Book Questions and Answers

Part I

Choose The Correct Answers

Question 1.
Which language is used to request information from a Database?
a) Relational
b) Structural
c) Query
d) Compiler
Answer:
c) Query

Question 2.
The …………….. diagram gives a logical structure of the database graphically?
a) Entity-Relationship
b) Entity
c) Architectural Representation
d) Database
Answer:
a) Entity-Relationship

Question 3.
An entity set that does not have enough attributes to form a primary key is known as
a) Strong entity set
b) Weak entity set
c) Identity set
d) Owner set
Answer:
b) Weak entity set

Question 4.
_____ Command is used to delete a database.
a) Delete database database_name
b) Delete database_name
c) drop database database_name
d) drop database_name
Answer:
c) drop database database_name

Question 5.
Which type of below DBMS is MySQL?
a) Object-Oriented
b) Hierarchical
c) Relational
d) Network
Answer:
c) Relational

Question 6.
MySQL is freely available and is open source.
a) True
b) False
Answer:
a) True

Question 7.
……………….. represents a “tuple” in a relational database?
a) Table
b) Row
c) Column
d) Object
Answer:
b) Row

Question 8.
Communication is established with MySQL using
a) SQL
b) Network calls
c) java
d) API’s
Answer:
a) SQL

Question 9.
Which is the MySQL instance responsible for data processing?
a) MySQL Client
b) MySQL Server
c) SQL
d) Server Daemon Program
Answer:
c) SQL

Question 10.
The structure representing the organizational view of the entire database is known as _____ In MySQL database.
a) Schema
b) View
c) Instance
d) Table
Answer:
a) Schema

Part II

Short Answers

Question 1.
Define Data Model and list the types of data model used.
Answer:
Data models define how the logical structure of a database is modeled.
Data models define how data is connected to each other and how they are processed and stored inside the system. The various data models are;

1. Hierarchical Database Model,
2. Network Model,
3. Relational Model and
4. Object-oriented Database Model.

Question 2.
List few disadvantages of the file processing system.
Answer:
Data Duplication – Same data is used by multi¬ple resources for processing, thus created multiple copies of the same data wasting the spaces.

High Maintenance – Access control and verify- ing data consistency needs high maintenance cost.
Security – Less security provided to the data.

Question 3.
Define Single and multi-valued attributes.
Answer:
A single-valued attribute contains only one value for the attribute and they don’t have multiple numbers of values. For Example Age.
A multi-valued attribute has more than one value for that particular attribute. For Example Degree.

Question 4.
List any two DDL and DHL commands with its Syntax.
Answer:
DDL Commands:

DML Commands:

Question 5.
What are the ACID properties?
Answer:
ACID Properties – The acronym stands for Atomicity, Consistency, Isolation and Durability. Atomicity follows the thumb rule “All or Nothing” while updating the data in the database for the user performing the update operation. Consistency ensures that the changes in data value to be constant at any given instance. Isolation property is needed during concurrent action. Durability is defined as the system’s ability to recover all committed actions during the failure of storage or the system.

Question 6.
Which command is used to make permanent changes done by a transaction?
Answer:

• These SQL commands manage the transactions in SQL databases.
• It also helps to save the change into the database permanently.
• COMMIT, ROLLBACK, SET TRANSACTION, and SAVEPOINT commands belong to this category.

Question 7.
What is a view in SQL?
Answer:
Views – A set of stored queries.

Question 8.
Write the difference between SQL and MySQL.
Answer:

Question 9.
What is a Relationship and List its types?
Answer:
One-to-One relationship
One-to-Many relationship
Many-to-Many relationship

Question 10.
State a few advantages of Relational databases.
Answer:

1. High Availability
2. High Performance
3. Robust transfer actions and support
4. Ease of management
5. Less cost

Part III

Explain In Brief Answer

Question 1.
Explain on Evolution of DBMS.
Answer:

1. The concept of storing the data started 40 years in various formats.
2. In earlier days they have used punched card technology to store the data.
3. Then files were used. The file systems were known as the predecessor of the database system.
4. Various access methods in the file system were indexed, random, and sequential access.
5. The file systems have limitations like duplication, less security. To overcome this, DBMS was introduced.

Question 2.
What is a relationship in databases? List its types.
Answer:
There exists a relationship between two tables when the foreign key of one table references the primary key of other tables.
The Entity-Relationship(ER) diagram is based on the three types listed below.

• One-to-One relationship
• One-to-Many relationship
• Many-to-Many relationship

Question 3.
Discuss on Cardinality in DBMS.
Answer:

• It is defined as the number of different values in any given table column
• It Is defined as the number of items that must be II included in a relationship.ie) number of entities | in one set mapped with the number of entities of I another set via the relationship,
• Three classifications in Cardinality are one-to-one, jl one-to-many and Many-to-Many.

Question 4.
List any 5 privileges available in MySQL for the User.
Answer:

Question 5.
Write few commands used by DBA to control the entire database.
Answer:
USE Database
This command is used to select the database in MySQL for working.
Syntax: mysql>use test;

SHOW Databases
Lists all the databases available in the database server,
Syntax: mysql>show databases;

SHOW Tables
Lists all the tables available in the current database we are working in.
Syntax: mysql>show tables;

Part IV

Explain In Detail

Question 1.
Discuss on various database model available in DBMS.
Answer:
The major database models are listed below:

• Hierarchical Database Model
• Network model
• Relational model
• Object-oriented database mode!

Hierarchical Database Model

• In this model each record has information in par-ent/child relationship like a tree structure.
• The collection of records was called as record types, which are equivalent to tables in relational model.
• The individual records are equal to rows.
• The famous Hierarchical database model was IMS (Information Management System), IBM’s first DBMS,

Advantages:

• Less redundant data
• Efficient search
• Data integrity
• Security

Limitations:

• Complex to implement and difficult in handling
• Many to many relationships

Network model

• The network model is similar to the Hierarchical model except that in this model each member can have
  more than one owner.
• The many to many relationships are handled in a better way.
• This model identified the three database components
• Network schema – Defines all about the structure of the database
• Sub schema – Controls on views of the database for the user.
• Language for data management – Basic procedural for accessing the database.

Relational model:

Oracle and DB2 are few commercial relational models in use.
The relational model is defined with two terminologies Instance and Schema.

• Instance – A table consisting of rows and columns
• Schema – Specifies the structure including the name and type of each column.

A relation (table) consists of unique attributes (columns) and tuples (rows).

Object-oriented database model

• This model incorporates the combination of Object-Oriented Programming(OOP’s) concepts and database technologies.
• Practically, this model serves as the base of the Relational model.
• The object-oriented model uses small, reusable software known as Objects.
• These are stored in an object-oriented database.
• This model efficiently manages a large number of different data types.
• Moreover, complex behaviors are handled efficiently using OOP’s concepts.

Question 2.
List the basic concepts of ER Model with suitable examples.
Answer:
The basic concepts of ER model consist of

• Entity or Entity type
• Attributes
• Relationship

These are the general concepts which help to create an ER diagram and produce an ER model.

Entity or Entity type:

• An Entity can be anything a real-world object or animation which is easily identifiable by anyone even by a common man.
• Example: In a company’s database Employees, HR, Manager are considered entities.
• An entity is represented by a rectangular box.

Types of Entity:

1. Strong Entity
2. Weak Entity
3. Entity Instance

Strong Entity

• A Strong entity is the one which doesn’t depend on any other entity on the schema or database
• A strong entity will have a primary key with it.
• It is represented by one rectangle

Weak Entity

• A weak entity is dependent on other entities and it doesn’t have any primary key like the Strong entity.
• It is represented by a double rectangle.

Entity Instance

• Instances are the values for the entity if we consider animals as the entity their instances will be dog, cat, cow… Etc.
• So an Entity Instance denotes the category values for the given entity.

Attributes:

• An attribute is the information about that entity and it will describe, quantify, classify, and specify an entity.
• An attribute will always have a single value, that value can be a number or character or string.

Types of attributes:

1. Key Attribute
2. Simple Attributes
3. Composite Attributes
4. Single Valued Attribute
5. Multi-Valued Attribute

Relationship:
There exists a relationship between two tables when the foreign key of one table references primary key of other table.
The Entity-Relationship(ER) diagram is based on the three types listed below.

• One-to-One relationship
• One-to-Many relationship
• Many-to-Many relationship

Question 3.
Discuss in detail various types of attributes in DBMS.
Answer:
Types of attributes:
1. Key Attribute:
Generally, a key attribute describes a unique characteristic of an entity.

2. Simple Attribute:

• The simple attributes cannot be separated it will be having a single value for their entity.
• For Example: Let us consider the name as the attribute for the entity employee and here the value for that attribute is a single value.

3. Composite Attributes:

• The composite attributes can be sub divided into simple attributes without change in the meaning of that attribute.
• For Example: In the above diagram the employee is the entity with the composite attri¬bute Name which are sub-divided into two simple attributes first and last name.

4. Single Valued Attributes;

• A single valued attribute contains only one value for the attribute and they don’t have multiple numbers of values.
• For Example: Age- It is a single value for a person as we cannot give n number of ages for a single person; therefore it is a single valued attribute.

5. Multi-Valued Attributes:

• A multi valued attribute has more than one value for that particular attribute.
• For Example: Degree – A person can hold n number of degrees so it is a multi-valued attribute.

Question 4.
Write a note on open-source software tools available in MySQL Administration.
Answer:

• MySQL is open source software that allows managing relational databases.
• It also provides the flexibility of changing the source code as per the needs.
• It runs on multiple platforms like Windows, Linux and is scalable, reliable and fast.

PHPMYADMIN (Web Admin)

• This administrative tool of MySQL is aweb application written in PHP. They are used predominantly in web hosting.
• The main feature is providing web interface,- importing data from CSV and exporting data to various formats.
• It generates live charts for monitoring MySQL server activities like connections, processes and memory usage. It also helps in making the complex queries easier.

MySQL Workbench (Desktop Application)

• It is a database tool used by developers and DBA’s mainly for visualization.
• This toolhelps in data modeling, development of SQLServer configuration and backup for MySQLin a better way.
• Its basic release version is 5.0and is now in 8.0 supporting all Operating Systems.
• The SQL editor of this tool is veryflexible and comfortable in dealing multiple results set.

HeidiSQL (Desktop Application)

• This open source tools helps in the administra-tion of better database systems.
• It supports GUI (Graphical User Interface) features for monitoring server host, server connection, Databases, Tables, Views, Triggers and Events.

Question 5.
Explain in detail on Sub Queries with suitable examples.
Answer:

• The SQL query is written within amain Query.
• This is called Nested Inner/SubQuery.
• The sub query is executed first and the results of sub query are used as the condition for main query.

The sub query must follow the below rules:

• Subqueries are always written within the parentheses.
• Always place the Subquery on the right side of the comparison operator.
• ORDER BY clause is not used insub query, since Subqueries cannot manipulate the results internally.

Example: (Consider the Employee tablewith the fields EmpID, Name, Age andSalary.)
SELECT * from Employee WHERE EmpID IN (SE-LECT EmpID from Employee WHERE Salary 20000);
First, the inner query is executed. Then outer query will be executed.

12th Computer Applications Guide Introduction to Database Management System Additional Important Questions and Answers

Part A

Choose The Correct Answers:

Question 1.
Expand DBMS?
(a) Database Management System
(b) Data Manipulation Schema
(c) Data Base Management Schema
(d) DataBase Manipulation Schema
Answer:
(a) Database Management System

Question 2.
DBMS provides to ………………… data
a) create
b) retrieve
c) update
d) all of the above
Answer:
d) all of the above

Question 3.
Expand ODBMS.
(a) Object DataBase Management System
(b) Objective Data Base Management System
(c) Object-Oriented DataBase Management System
(d) Objective Data Manipulation System
Answer:
(a) Object DataBase Management System

Question 4.
……………. is defined as the system’s ability to recover all committed transactions during the failure of storage or the system.
a) Durability
b) Consistency
c) Concurrency
d) All of the above
Answer:
a) Durability

Question 5.
Which of the following is a commercial relational models in use.
a) Oracle
b) DB2
c) PostgreSQL
d) Both a and b
Answer:
d) Both a and b

Question 6.
To prevent conflict in database updates, the transactions are isolated from other users and serialized. This is called as ……………………….
(a) Atomicity
(b) Consistency
(c) Isolation
(d) Degree of Consistency
Answer:
(d) Degree of Consistency

Question 7.
A key with more than one attribute to identify rows uniquely in a table is called…………….
a) Candidate Key
b) Super Key
c) Foreign Key
d) Composite Key
Answer:
d) Composite Key

Question 8.
An …………….  can be anything a real-world object or animation
a) Data
b) Entity
c) Instance
d) Relationship
Answer:
b) Entity

Question 9.
Concurrency control and locking are needed
(a) Consistency
(b) data sharing
(c) data hiding
(d) TrAnswer:action
Answer:
(b) data sharing

Question 10.
………… describes a unique characteristic of an entity.
a) Key Attribute
b) Simple Attributes
c) Composite Attributes
d) Single Valued Attribute
Answer:
a) Key Attribute

Question 11.
………… can be subdivided into simple attributes without change in the meaning of that attribute.
a) Key Attribute
b) Simple Attributes
c) Composite Attributes
d) Single Valued Attribute
Answer:
c) Composite Attributes

Question 12.
A …………. contains only one value for the attribute and they don’t have multiple numbers of values.
a) Key Attribute
b) Simple Attributes
c) Composite Attributes
d) Single Valued Attribute
Answer:
d) Single Valued Attribute

Question 13.
IBM’s first DBMS is ……………………..
(a) IMS
(b) IVS
(c) BMS
(d) VMS
Answer:
(a) IMS

Question 14.
A ……………. has more than one value for that particular attribute.
a) Multi-valued attribute
b) Simple Attributes
c) Composite Attributes
d) Single Valued Attribute
Answer:
a) Multi-valued attribute

Question 15.
The parent-child relationship is established in …………………….. database Models.
(a) Hierarchical
(b) Network
(c) Relational
(d) Object
Answer:
(a) Hierarchical

Fill in the Blanks:

1. ………………is known a predecessor of database system
Answer:
File system

2. MySQL is a database management system founded by…………………
Answer:
Monty Widenius

3. ……………who takes care of configuration, installation, performance, security and data backup.
Answer:
Database Administrators

4. …………….. is a web application written in PHP
Answer:
PHPMYADMIN

5. ………………tool of MySQL is a web application written in PHP.
Answer:
PHPMYADMIN

6. ………………….. is a database tool used by developers and DBA’s mainly for visualization.
Answer:
MySQL Workbench

Question 7.
The ……………….. of this tool is very flexible and comfortable in dealing with multiple results set.
Answer:
SQL editor

Question 8.
…………………….. is a program or process of copying table contents into a file for future reference
Answer:
Backup

Question 9.
SQL query is written within a main Query is called as
Answer:
Sub Query

Question 10.
An attribute is the information about that …………………
Answer:
Entity

Abbrevation

1. DBMS – Database Management System.
2. RDBMS – Relation Database Management System.
3. OSBMS – Objective Database Management System.
4. ACID – Automicity, Consistency, Isolation, And Durability.
5. IMS – Information Management System.
6. IDS – Integrated Data Store.
7. OOP’S – Object Oriented Programming.
8. SQL – Structure Query Language.
9. ER – Entity Relationship.
10. DBA – Database Administration.
11. ANSI – American National Standards Institute.
12. ISO – International Organization For Standardization.
13. DDL – Data Definition Language.
14. DML – Data Manipulation Language.
15. DQL – Data Query Language.
16. TCL – Transaction Control Language.
17. DCL – Data Control Language.

Assertion And Reason

Question 1.
Assertion (A): database management system (DBMS) is system software for creating and managing databases.
Reason (R): The DBMS provides users and programmers with a systematic way to create, retrieve, update and manage data.”
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) is false
d) (A) is false and (R) is true
Answer:
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)

Question 2.
Assertion (A) : In a database, we would be grouping only related data together and storing them under one group name called table.
Reason (R): This helps in identifying which data stored where and under what name.
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) is false
d) (A) is false and (R) ¡s true
Answer:
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)

Question 3.
Assertion (A): Oracle and DB2 are few commercial relational models in use.
Reason (R): Relational model is defined with two terminologies Instance and Schema.
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) is false
d) (A) is false and (R) ¡s true
Answer:
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)

Question 4.
Assertion (A): A single-valued attribute con¬tains only one value for the attribute and they don’t have multiple numbers of values.
Reason (R): Age – It is a single value for a person as we cannot give n number of ages for a single person, therefore it is a single-valued attribute.
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) Is false
d) (A) is false and (R) is true
Answer:
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)

Question 5.
Assertion (A): Cardinality is defined as the number of items that must be included in a relationship.ie) number of entities in one set mapped with the number of entities of another set via the relationship.
Reason (R): Three classifications in Cardinality areMany-to-one, one-to-many and Many-to-Many,
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) is false
d) (A) is false and (R) is true
Answer:
c) (A) is true and (R) is false

Question 6.
Assertion (A): The Database Administrator (DBA) frequently uses few commands to control the entire database.
Reason (R): These commands are known as SQL Server Commands.
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) is false
d) (A) is false and (R) is true
Answer:
c) (A) is true and (R) is false

Question 7.
Assertion (A); Subqueries are always written within the braces.
Reason (R): ORDER BY clause is not used in sub query, since Subqueries cannot manipulate the results internally.
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) is false
d) (A) is false and (R) is true
Answer:
d) (A) is false and (R) is true

Question 8.
Assertion (A); TCL commands manage the transactions in SQL databases. It also helps to save the change into database permanently.
Reason (R) : CREATE, ALTER, DROP, RENAME and TRUNCATE commands belongs to TCL category.
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) is false
d) (A) is false and (R) is true
Answer:
c) (A) is true and (R) is false

Question 9.
Assertion (A); A Strong entity is the one which doesn’t depend on any other entity on the schema or database and a strong entity will have a primary key with it
Reason (R): It is represented by one rectangle.
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) is faise
d) (A) is false and (R) is true
Answer:
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)

Question 10.
Assertion (A) ; A weak entity is dependent on other entitles and it doesn’t have any primary key like the Strong entity.
Reason (R): It is represented by Diamond,
a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A)
c) (A) is true and (R) is false
d) (A) is false and (R) is true
Answer:
c) (A) is true and (R) is false

Find the odd one on the following:

1. (a) Sorting
(b) Retrieving
(c) Filtering
(d) Aligning
Answer:
(d) Aligning

2. (a) Creating
(b) Updating
(c) Managing
(d) Converting
Answer:
(d) Converting

3. (a) Data Duplication
(b) Data Flexibility
(c) Data Maintenance
(d) Security
Answer:
(c) Data Maintenance

4. (a) Access
(b) SQL
(c) Oracle
(d) Notepad
Answer:
(b) SQL

5. (a) Consistency
(b) Durability
(c) Activity
(d) Isolation
Answer:
(c) Activity

6. (a) DBMS
(b) Network Schema
(c) Subschema
(d) Language
Answer:
(a) DBMS

7. (a) id:int
(b) name:int
(c) Nfname:string
(d) email:string
Answer:
(b) name:int

8. (a) Table
(b) attribute
(c) files
(d) Tuples
Answer:
(c) files

9. (a) Class
(b) Object
(c) Data
(d) Abstraction
Answer:
(c) Data

10. (a) Schema
(b) Key
(c) Tuple
(d) Cell
Answer:
(d) Cell

11. (a) Windows
(b) Linux
(c) MACOS
(d) MSSQLServer
Answer:
(d) MSSQLServer

12. (a) Row
(c) Record
(b) attribute
(d) Tuple
Answer:
(b) attribute

13. (a) Vertical Entity
(b) Attribute
(c) Tuple
(d) column
Answer:
(c) Tuple

14. (a) primary Key
(b) Secondary Key
(c) SuperKey
(d) Foreign Key
Answer:
(b) Secondary Key

15. (a) Strong Entity
(c) Super Entity
(b) Weak Entity
(d) Entity Instance
Answer:
(c) Super Entity

16. (a) Schema
(b) Database
(c) primary Key
(d) Foreign Key
Answer:
(d) Foreign Key

17. (a) Degree
(b) Bank Account
(c) Age
(d) Subjects
Answer:
(c) Age

18. (a) One:Unary
(b) Two: Binary
(c) Three:Ternary
(d) Four: penta
Answer:
(d) Four: penta

19. (a) Rectangle
(b) Square
(c) Rhombus
(d) Ellipse
Answer:
(b) Square

20. (a) DB2
(b) Netfix
(c) SQL Lite
(d) Oracle
Answer:
(b) Netfix

21. (a) Configuration
(b) Installation
(c) Performance
(d) Access
Answer:
(d) Access

22. (a) INSERT
(b) EDIT
(c) SELECT
(d) UPDATE
Answer:
(b) EDIT

23. (a) Select_Priv
(b) Delete_Priv
(c) create_Priv
(d) Edit_Priv
Answer:
(d) Edit_Priv

24. (a) MySQL
(b) Workbench
(c) PHPMYADMIN
(d) HeidiSQL
Answer:
(c) PHPMYADMIN

25. (a) ServerHost
(b) Server Connection
(c) Events
(d) processor
Answer:
(d) processor

26. (a) Dashboard
(b) Reports
(c) Table
(d) Statistics
Answer:
(c) Table

27. (a) Table
(b) Insert
(c) Queries
(d) Views
Answer:
(b) Insert

28. (a) TRUNCATE
(b) RENAME
(c) SELECT
(d) ALTER
Answer:
(c) SELECT

29. (a) DDL
(b) DML
(c) HeidiSQL
(d) DQL
Answer:
(c) HeidiSQL

30. (a) ANY
(b) AND
(c) UNIQUE
(d) XOR
Answer:
(d) XOR

MAtch the following:

1. Hierarchical Database – Sybase
2. Network Database – Rhombus
3. Relational Database – Multivalued Attribute
4. Column – Candidate Key
5. Row – Record
6. Primary key – Attribute
7. Super Key – Unique Key Identifier
8. Double Ellipse – Oracle
9. Relationships – IMS
10. Database – IDS
Answer:
1. IMS
2. IDS
3. Oracle
4. Attribute
5. Record
6. Unique Key
7. Candidate Key
8. Multivalued Attribute
9. Rhombus
10. Sybase

Choose the incorrect statements:

Question 1.
a) SQL It (Structured query Language) is a programming language designed mainly for . managing data in RDBMS
b) Schema Retrieves data from two or more tables, by referencing columns in the tables that hold identical values
c) Query In SQL, all commands are named as query. The query statement is executed against the databases.
d) Record is referred in a table, which are composed of fields.
Answer:
b) Schema Retrieves data from two or more tables, by referencing columns in the tables that hold identical values

Question 2.
a) A Record is the information about that entity and it will describe, quantify, qualify, classify, and specify an entity.
b) Cardinality is defined as the number of items that must be included in a relationship
c) A multi-valued attribute has more than one value for that particular attribute.
d) A single-valued attribute contains only one value for the attribute and they don’t have multiple numbers of values.
Answer:
a) A Record is the information about that entity and it will describe, quantify, qualify, classify, and specify an entity.

Question 3.
a) Network schema defines all about the structure of the database.
b) Sub schema controls on views of the database for the user
c) The famous Hierarchical database model was IDS
d) Language is the basic procedural for accessing the database.
Answer:
c) The famous Hierarchical database model was IDS

Question 4.
a) A table consisting of rows and columns
b) Schema – Specifies the structure including name and type of each column.
c) A relation consists of unique attributes and tuples.
d) Query is referred in a table, which are composed of fields.
Answer:
d) Query is referred in a table, which are composed of fields.

Question 5.
a) DCL commands manage the transactions
b) The DML commands deals with the manipulation of data present in the database
c) SELECT is the only SQL command used to fetch or retrieve the data from database tables that come under DQL.
d) The DDL commands are used to define database schema (Structure)
Answer:
a) DCL commands manage the transactions

Syntax & Example (Basic Sql Commands)

1) CREATE DATABASE:
Syntax: CREATE database databasename;
Example: mysql> create database studentDB;

2) DROP DATABASE:
Syntax: DROP database databasename;
Example: mysql> drop database studentDB;

3) SELECT DATABASE
Syntax: USE databasename;
Example: mysqi> USE studentDB;

4) INSERT RECORD
Syntax 1: INSERT INTO tablename (columnl, column 2, column 3) Values(vaiue 1, value 2, value 3)
Syntax 2: INSERT INTO tablename
Values(value 1, va!ue2, value3)

5) DELETING RECORD :
Syntax 1; DELETE for tablename WHERE Coiumnname =” value ”
Syntax 2; DELETE for tablename

6) MODIFYING RECORD:
Syntax : UPDATE tablename SET column 1= “newvalue” where column 2= value2

7) SORTING RECORD:
Syntax 1 SELECT * FROM TABLENAME ORDER BY COLUMNNAME;
Syntax 2 select * from tablename ORDER BY columnname DESC;

Part B

Short Answers

Question 1.
Define database?
Answer:
“A database management system (DBMS) is system software for creating and managing databases. The DBMS provides users and programmers with a systematic way to create, retrieve, update and manage data”.

Question 2.
Define DBMS
Answer:
Definition;

• A database management system (DBMS), is system software for creating and managing databases.
• The DBMS provides users and programmers with a systematic way to create, retrieve, update and manage data.

Question 3.
Define degree of consistency?
Answer:
To prevent conflict in database updates, the transactions are isolated from other users and serialized. This is also known as the Degree of Consistency.

Question 4.
What are the limitations of the database?
Answer:

• Data Duplication
• High Maintenance
• Security

Question 5.
Write the various forms of the database.
Answer:

• Relational Database Management System (RDBMS)
• And Object Database Management System (ODBMS).

Question 6.
Define relational database?
Answer:
Any database whose logical organization is based on a relational data model is known as Relational Database.

Question 7.
What do you mean by the table in the Relational database model?
Answer:
In relational database model,

• The table is defined as the collection of data organized in terms of rows and columns.
• The table is the simple representation of relations. The true relations cannot have duplicate rows

Question 8.
Write the types of SQL commands.
Answer:

• Data Definition Language (DDL)
• Data Manipulation Language (DML)
• Data Query Language (DQL)
• Transaction Control Language (TCL)
• Data Control Language (DCL)

Question 9.
Define Primary key?
Answer:

1. The candidate key that is chosen to perform the identification task is called the primary key and any others are Alternate keys.
2. Every tuple must-have, a unique value for its primary key.

Question 10.
What is XAMPP?
Answer:

• XAMPP is a free and open-source package.
• It was developed by Apache.
• It is a software platform for MySQL, PHP and Peri programming languages.

Question 11.
Define Composite key?
Answer:
A key with more than one attribute to identify rows uniquely in a table is called a Composite key. This is also known as Compound Key.

Part C

Explain In Brief Answer.

Question 1.
Explain three database components of the network model?
Answer:
The three database components of Network models are Network schema, Sub schema, and Language.
Network schema – schema defines all about the structure of the database.
Sub schema – controls on views of the database for the user.
Language – basic procedural for accessing the database.

Question 2.
List few commonly used databases.
Answer:

• DB2
• MySQL
• Oracle
• PostgreSQL
• SQLite
• SQL Server
• Sybase

Question 3.
What are the roles of a Database administrator?
Answer:

• Database Administrators (DBA’s) who takes care of configuration, installation, performance, security and data backup.
• DBA’s possess the skills on database design, database queries, RDMS, SQL and networking.
• The primary task is the creation of new user and providing them with access rights.

Question 4.
Define Super key?
Answer:

1. An attribute or group of attributes, which is sufficient to distinguish every tuple in the relation from every other one is known as Super Key.
2. Each super key is called a candidate key.
3. A candidate key is selected from the set of Super Key.

Question 5.
Write a note on MySQL.
Answer:

• The candidate key that is chosen to perform
• MySQL is a database management system founded by Monty Widenius
• MySQL is open-source software that allows managing relational databases.
• It also provides the flexibility of changing the source code as per the needs.
• It runs on multiple platforms like Windows, Linux and is scalable, reliable and fast.

Question 6.
Write a short note on Row (or Record or tuple)
Answer:

• A single entry in a table is called a Row or Record or Tuple.
• Set of related data are represented in a row or tuple.
• The horizontal entity in a table is known as a Record or row.

Question 7.
Give the roles and responsibilities of DBA?
Answer:
Database Administrators (DBA’s) take care of configuration, installation, performance, security, and data backup.
DBA’s possess the skills in database design, database queries, RDMS, SQL, and networking.
The primary task is the creation of new users and providing them with access rights.

Part D

Explain in detail.

Question 1.
Explain the following:

1. Primary Key
2. Foreign Key
3. Candidate Key
4. Super Key
5. Composite key

Answer:
1. Primary Key:

• This key of the relational table identifies each record in the table in a unique way.
• A primary key which is a combination of more than one attribute is called a composite primary key.
• The candidate key that is chosen to perform the identification task is called the primary key

2. Foreign Key:

• A foreign key is a “copy” of a primary key that has been exported from one relation into another to represent the existence of a relationship between them.
• A foreign key is a copy of the whole of its parent primary key i.e if the primary key is composite, then so is the foreign key.
• Foreign key values do not (usually) have to be unique.
• Foreign keys can also be null.
• A composite foreign key cannot have some attribute(s) null and others non-null.

3. Candidate Key:

• Each super key is called a candidate key.
• A candidate key is selected from the set of Super Key.
• While selecting the candidate key, redundant attributes should not be taken.
• The candidate key is also known as minimal super keys.

4. Super Key:
An attribute or group of attributes, which is sufficient to distinguish every tuple in the relation from every other one is known as Super Key.

5. Composite Key (Compound Key): A key with more than one attribute to identify rows uniquely in a table is called a Composite key. This is also known as Compound Key.

Question 2.
Tabulate the ER diagram notations
Answer:

Tamilnadu State Board New Syllabus Samacheer Kalvi 11th Commerce Guide Pdf Chapter 1 Historical Background of Commerce in the Sub-Continent Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 11th Commerce Solutions Chapter 1 Historical Background of Commerce in the Sub-Continent

11th Commerce Guide Historical Background of Commerce in the Sub-Continent Text Book Back Questions and Answers

I. Choose the Correct Answer

Question 1.
The place where the goods are sold is ………………
a) Angadi
b) Market .
c) Nalangadi
d) Allangadi
Answer:
a) Angadi

Question 2.
Hindrance of place is removed by ……………………….
a) Transport
b) Warehouse
c) Salesman
d) Insurance
Answer:
a) Transport

Question 3.
Who wrote “Arthasasthra”?
a) Kautilya
b) Chanakiya
c) Thiruvalluvar
d) Elangovadiga
Answer:
a) Kautilya

Question 4.
Trade and Commerce was common to …………………….. Dynasty.
a) pallava
b) Chola
c) Panidya
d) Chera
Answer:
c) Panidya

Question 5.
…………………….. was first sultan who paved way in the dense forest and helped traders to move from one market place to others place for
their commercial caravans.
a) Balban
b) Vascoda Gama
c) Akbar
d) Alauddin Khilij
Answer:
a) Balban

II. Very Short Answer Questions

Question 1.
What is meant by the Barter system?
Answer:
Goods were exchanged for goods prior to the invention of money.

Question 2.
What is meant by Nallangadi?
Answer:
According to St.Poet Ilango, in Silapathigaram, a Day Market was called Nalangadi.

Question 3.
What is meant by Allangadi?
Answer:
The night market was called Allangadi according to Saint Poet Ilango in Silapathigaram, Madurai-Kanchi.

III. Short Answer Questions

Question 1.
Explain the meaning of the term “Vanigam”.
Answer:
The word vaniyam or vanipam would have had a Dravidian origin. The early Tamils produced their products and goods in their lands and bartered their surplus and that is how the trade came into existence. The word ‘Vanigam is used in Sangam literature like Purananuru and Thirukkural.

Question 2.
State the meaning of Maruvurapakkam and Pattinapakkam.
Answer:
Big cities like Poompuhar had the ‘Maruvurappakam’ (inland town) and ‘Pattinapakkam’ (coastal town), had markets and bazaars where many merchants met one another for the purpose of selling or buying different kinds of commodities and foodstuff.

Question 3.
What is the role of Sangam in trade development of ancient Tamilnadu?
Answer:
Trade in Sangam period was both internal and external. It was conducted by means of barter (Pandamattru). Honey, roots, fruits, cattle and paddy served as a medium of exchange for certain period. Sangam work refers to great traders, their caravans, their security force, markets, marts and guilds of such traders. There was dependence and interdependence among the people in matters of trade and commerce. Coins were used later for the purpose of exchange of goods.

Question 4.
What are the ports developed by Pandiya kingdom?
Answer:
Port towns like Tondi, Korkai, Puhar, and Muziri were always seen as busy with marts and markets with activities related to imports and exports. In such a brisk trade, people of the coastal region engaged themselves in coastal trade and developed their intercontinental trade contacts.

Question 5.
What was focused in Arthasasthra about creation of wealth?
Answer:
Kautilya’s Arthasasthra describes the economy in Mauriyan time. Kautilya gave importance to the state in relation to treasury, taxation,  industry, commerce, agriculture, and conservation of natural resources. Arthasastra focused on the creation of wealth as the means to promote the well-being of the state. It advocated the maintenance of a perfect balance between the state government and people’s welfare through trading activities.

IV. Long Answer Questions

Question 1.
What are the hindrances of business?
Answer:
Hindrances of business:

1. Hindrance of Person: Manufacturers do not know the place and face of the consumers. It is the retailer who knows the taste, preference, and location of the consumers. The chain of middlemen consisting of wholesalers, agents, and retailers establish the link between the producers and consumers.
2. Hindrance of Place: Production takes place in one centre and consumers are spread throughout the country and world. Rail, air, sea, and land transports bring the products to the place of the consumer.
3. Hindrance of Time: Consumers want products whenever they have money, time, and willingness to buy. Goods are produced in anticipation of such demands.
4. Hindrance of risk of deterioration in quality: Proper packaging and modern air-conditioned storage houses ensure that there is no deterioration in the quality of products.
5. Hindrance of risk of loss: Fire, theft, floods, and accidents may bring huge losses to the business.
6. Hindrance of knowledge: Advertising and communication help in announcing the arrival of new products and their uses to the people.
7. Hindrance of exchange: Money functions as a medium of exchange and enables the buying and selling of any product or service by payment of the right price.
8. Hindrance of finance: Producers and traders may not have the required funds at the time of their need.
9. Hindrance of developing the exact product: Research and development help in developing the exact product or service which can satisfy the specific wants of consumers and thus improve the standard of living of the people.
10. Hindrance of both selection and delivery at doorsteps: E-Commerce enables the consumer to select the product on the website, place online orders, and make payment after receiving the product at the doorstep.

Question 2.
State the constraints in the barter system.
Answer:
The barter system visualises mutual exchange of one’s goods to another without the intervention of money as a medium of exchange. It imposes certain constraints in the smooth flow of trade as given below.

• Lack of double coincidence of Wants: Unless two persons who have surplus have the demand for the goods possessed by each other, barter could not materialize.
  For instance ‘A’ is having a surplus of groundnut and ‘B’ is possessing rice in surplus. In this case A should be in need of rice possessed by B as the latter should
• The non-existence of common measure of value: The barter system could not determine the value of commodities to be exchanged as they lacked commonly acceptable measures to evaluate each and every commodity. It was difficult to compare the values of all articles in the absence of an acceptable medium of exchange.
• Lack of direct contact between producer and consumers: It was not possible for buyers and sellers to meet face to face in many contexts
  for exchanging the commodities for commodities. This hindered the process of barter in all practical sense.
• Lack of surplus stock: The absence of surplus stock was one of the impediments in the barter system. If the buyers and sellers do not have a surplus then no barter was possible.

Question 3.
Explain the development of Commerce and Trade in North India.
Answer:
India was prosperous even during the medieval period from the 12^th to 16^th centuries despite political upheavals. Balban was the first sultan who paved the way in the dense forest and helped traders and their commercial caravans to move from one marketplace to another. Allauddin Khilji brought the price to a very low ebb. He encouraged the import of foreign goods from Persia and subsidized the goods.

Arabs were dominant players in India’s foreign trade. They never discouraged Indian traders like Tamils, Gujaratis, etc. The trade between the coastal ports was in the hands and Marwaris and Gujaratis, The overland trade with central and west Asia was in the hands of Multanis who were Hindus, and Khurasanis who were Afghans, Iranians, and so on.

Question 4.
Briefly explain the coastal trade in ancient Tamilnadu.
Answer:
People of the coastal region engaged themselves in coastal trade and developed their intercontinental trade contacts. Big cities like Poompuhar had ‘Maruvurappakkam’(inland town) and ‘Pattinapakkam’(coastal Town), had markets and bazaars where many merchants met one another for the purpose of selling or buying different commodities and foodstuff. Port towns like Tondi, Korkai, Puhar, and Muziri were involved in imports and exports.

People were engaged in different kinds of fishing pearls, and conches and produced salts, and built ships. Boats like ‘Padagu’,’Thimil’,’Thoni’,’Ambu’, ‘Odampunai’ etc. were used to cross rivers for domestic trade while Kalam, Marakalam, Vangam, Navaietc were used for crossing oceans for foreign trade.

Question 5.
What do you know about the overseas trading partners of ancient Tamilnadu?
Answer:
Foreigners who transacted business were known as Yavanars. Arabs who traded with Tamil were called ‘Jonagar’. Pattinappalai praised Kaveripumpattinam as a city where various foreigners of high civilization speaking different languages assembled to transact business with the support of the then Kingdom.

Many ports were developed during the Sangam period. Kaveripumpattinam was the chief port of the Kingdom of Cholas while Nagapattinam, Marakannam, Arikamedu, etc., were other small ports on the east coast. Similarly, Pandiyas developed Korkai, Saliyur, Kayal, Marungaurpattinam, and Kumari for foreign trade. The State Governments installed check posts to collect customs along the highways and the ports.

11th Commerce Guide Historical Background of Commerce in the Sub-Continent Additional Important Questions and Answers

I Choose the correct answer

Question 1.
…………….. is part and parcel of human life.
(a) Commerce
(b) Banking
(c) Insurance
(d) Warehousing
Answer:
(a) Commerce

Question 2.
Most of the inland trade in the Sangam period was done in, ………………………………. as a medium of exchange under barter mode.
a) Salt
b) Coin
c) Milk
d) Gold
Answer:
a) Salt

Question 3.
Commerce activities are heading for a cashless system through ……………..
(a) e-commerce
(b) banking
(c) insurance
(d) warehousing
Answer:
(a) e-commerce

Question 4.
The night market was called…………………………..
a) Nalangadi
b) Angadi
c) Iravu Santhai
d) Allangadi
Answer:
d) Allangadi

Question 5.
Day market was called as ……………..
(a) Nalangadi
(b) Angadi
(c) Business
(d) Trade
Answer:
(a) Nalangadi

Question 6.
Foreigners who transacted business were known as ………………..
a) Jonagar
b) Sellers
c) Yavanars
d) Merchants
Answer:
c) Yavanars

Question 7.
Which is called a sleepless city?
(a) Chennai
(a) Allangadi
(c) Tuticorin
(d) Salem
Answer:
(a) Allangadi

Question 8.
………………………………. was the first sultan who paved in the dense forest and helped traders.
a) AlauddinKhilji
b) Balban
c) Suleiman I
d) Abdulaziz I
Answer:
c) Suleiman I

Question 9.
Boats like …………….. were used for crossing oceans for foreign trade.
(a) Vangam
(b) Thimil
(c) Ambu
(d) Thoni
Answer:
(a) Vangam

Question 10.
The hindrance of the place is removed by means of ……………….
a) Warehouse
b) Transport
c) Exchange of money
d) Insurance
Answer:
b) Transport

II. Very Short Answer Questions

Question 1.
What is the cashless system?
Answer:
Commerce activities are heading for a cashless system through e-commerce which means business activities enabled through electronic modes like Online trading, Mobile banking, and e-marketing.

Question 2.
What do you mean by “Angadi”?
Answer:
The place where the goods were sold was called “ Angadi”.

Question 3.
Which city was called sleepless city?
Answer:
Madurai was called a sleepless city due to round-the-clock business activities.

Question 4.
What was advocated by Kautilya in Arthasasthra with regard to trade?
Answer:
In Arthasasthra Kautilya advocated the maintenance of perfect balance between State management and people’s welfare through trading activities.

Question 5.
What type of boats were used to cross oceans for foreign trade?
Answer:
Boats like ‘Kalam’, ‘Marakalam’, ‘Vangam’, ‘Navai’, etc., were used for crossing oceans for foreign trade.

Question 6.
Which are all considered the important trade centres in the 16th century?
Answer:
In 16th Century Delhi, Mumbai, Ahmedabad, Sonar, Sonargoon. Jaunpur and Lahore were considered as important trade centres.

Question 7.
What was the role of the state in trade?
Answer:
The role of the state in trade related to two aspects namely adequate infrastructure to sustain the trade and administrative machinery for taxation.

Question 8.
With whom Cholas had a strong trading relationship?
Answer:
Cholas had a strong trading relationship with the Chinese Song Dynasty.

III. Short Answer Questions

Question 1.
How has the commerce activities emerged how?
Answer:
The whole of commerce activity has emerged from the barter system into a multi-dimensional and multifaceted scientific system consisting of courses like Monetary system, Mail order business, Hire purchase system, Instalment purchase system and so on.

Question 2.
What are all the conditions under Barter System worked on?
Answer:

• Each party to barter must have surplus stocks for the trade to take place.
• Both the buyers and sellers should require the goods to each other desperately, i.e., double coincidence of wants.
• Buyer and seller should meet personally to affect the exchange.

IV. Long Answer Questions

Question 1.
How did the ancient Tamil country trade with Rome, China, and Europe?
Answer:
Roman and Greek traders frequented the ancient Tamil country and forged trade relationships with ancient Kings of Pandiya, Chola, and Chera dynasties. Cholas had a strong trading relationship with the Chinese Song Dynasty. The Cholas conquered the Sri Vijaya Empire of Indonesia and Malaysia to secure a sea trading route to China. During the 16^th and 18^th centuries, India’s overseas trade expanded due to trading with European companies. The discovery of new all sea routes from Europe to India via the Cape of Good Hope by Vasco da Gama had a far-reaching impact on the civilized world. The arrival of the Portuguese in India was followed by the advent of other European communities. They gained a strong foothold in India’s maritime trade by virtue of their strong naval power.

Tamilnadu State Board New Syllabus Samacheer Kalvi 12th Physics Guide Pdf Chapter 7 Dual Nature of Radiation and Matter Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 12th Physics Solutions

Chapter 7 Dual Nature of Radiation and Matter

12th Physics Guide Dual Nature of Radiation and Matter Text Book Back Questions and Answers

Part – 1:

Text Book Evaluation:

I. Multiple Choice Questions:

Question 1.
The Wavelength λ_e of an electron and λ_p of a photon of same energy E are related
by
a) λ_p α λ_e
b) λ_p α \(\sqrt{\lambda_{e}}\)
c) λ_p α \(\frac{1}{\sqrt{\lambda_{e}}}\)
d) λ_p α λ_e²
Answer:
d) λ_p α λ_e²
Solution:

Question 2.
In an electron microscope, the electrons are accelerated by a voltage of 14 kV. If the voltage is changed to 224 kV, then the de Brogue wavelength associated with the electrons would
a) increase by 2 times
b) decrease by 2 times
c) decrease by 4 times
d) increase by 4 times
Answer:
c) decrease by 4 times
Solution:

Question 3.
A particle of mass 3 × 10^-6 g has the same wavelength as an electron moving with a velocity 6 × 10⁶ m s^-1. The velocity of the particle is
a) 1.82 × 10^-18 ms^-1
b) 9 × 10^-2 ms^-1
c) 3 × 10^-31 ms^-1
d) 1.82 × 10^-15 ms^-1
Answer:
d) 1.82 × 10^-15 ms^-1
Solution:

Question 4.
When a metallic surface is illuminated with radiation of wavelength λ, the stopping potential is V. If the same surface is illuminated with radiation of wavelength 2λ, the stopping potential is V/4. The threshold wavelength for the metallic surface is
a) 4λ
b) 5λ
c) \(\frac{5}{2}\)λ
d) 3λ
Answer:
d) 3λ
Solution:
hν – hν₀ = eV
\(\frac{\mathrm{hc}}{\lambda}-\frac{\mathrm{hc}}{\lambda_{\mathrm{o}}}\) = eV ………(1)
\(\frac{\mathrm{hc}}{2 \lambda}-\frac{\mathrm{hc}}{\lambda_{\mathrm{a}}}\) = \(\frac{\mathrm{eV}}{4}\) …………(2)
From (1) and (2)

Question 5.
If light of wavelength 330 nm is incident on metal with work function 3.55 eV, the electrons are emitted. Then the wavelength of the emitted electron is (Take h = 6.6 × 10^-34 Js)
a) < 2.75 × 10^-9 m
b) ≥ 2.75 × 10^-9 m
c) ≤ 2.75 × 10^-12 m
d) < 2.5 × 10^-10 m
Answer:
b) ≥ 2.75 × 10^-9 m
Solution:
hv – Φ₀ = \(\frac{1}{2}\) mv² = K.E

Question 6.
A photoelectric surface is illuminated successively by monochromatic light of wavelength λ and λ/2. If the maximum kinetic energy of the emitted photoelectrons in the second case is 3 times that in the first case, the work function at the surface of material is
a) \(\frac{\mathrm{hc}}{\lambda}\)
b) \(\frac{2 h c}{\lambda}\)
c) \(\frac{\mathrm{hc}}{3 \lambda}\)
d) \(\frac{\mathrm{hc}}{2 \lambda}\)
Answer:
d) \(\frac{\mathrm{hc}}{2 \lambda}\)
Solution:

Question 7.
In photoelectric emission, radiation whose frequency is 4 times the threshold frequency of a certain metal is incident on the metal. Then the maximum possible velocity of the emitted electron will be
a) \(\sqrt{\frac{\mathrm{hv}_{0}}{\mathrm{~m}}}\)
b) \(\sqrt{\frac{6 h v_{0}}{m}}\)
c) \(2 \sqrt{\frac{\mathrm{hv}_{0}}{\mathrm{~m}}}\)
d) \(\sqrt{\frac{\mathrm{hv}_{0}}{2 \mathrm{~m}}}\)
Answer:
b) \(\sqrt{\frac{6 h v_{0}}{m}}\)
Solution:
ν = 4ν₀
ν = ?
hν – hν₀ = \(\frac{1}{2}\) mv²

4hν₀ – hν₀ = \(\frac{1}{2}\) mv²

3hν₀ = \(\frac{1}{2}\) mv²

ν² = \(\frac{6 \mathrm{~h} v_{\mathrm{o}}}{\mathrm{m}}\)

⇒ ν = \(\sqrt{\frac{6 h v_{0}}{m}}\)

Question 8.
Two radiations with photon energies 0.9 eV and 3.3 eV respectively are falling on a metallic surface successively. If the work function of the metal is 0.6 eV, then the ratio of maximum speeds of emitted electrons will be
a) 1 : 4
b) 1 : 3
c) 1 : 1
d) 1 : 9
Answer:
b) 1 : 3
Solution:
\(\frac{1}{2}\) mv² = \(\frac{\mathrm{hc}}{\lambda}\)
\(\frac{1}{2}\) mv₁² = 0.9 – 0.6 = 0.3 ……………….(1)
\(\frac{1}{2}\) mv₂² = 3.3 – 0.6 = 2.7 ……………….(2)
eqn (1) / (2)
\(\frac{v_{1}^{2}}{v_{2}^{2}}\) = \(\frac{0.3}{2.7}=\frac{1}{9}\)

\(\frac{v_{1}}{v_{2}}=\sqrt{\frac{1}{9}}=\frac{1}{3}\)
ν₁ : ν₂ = 1 : 3

Question 9.
A light source of wavelength 520 nm emits 1.04 × 10¹⁵ photons per second while the second source of 460 nm produces 1.38 × 10¹⁵ photons per second. Then the ratio of power of second source to that of first source is
a) 1.00
b) 1.02
c) 1.5
d) 0.98
Answer:
c) 1.5
Solution:

Question 10.
The mean wavelength of light from the sun is taken to be 550 nm and its mean power is 3.8 × 10²⁶ W. The number of photons received by the human eye per second on average from sunlight is of the order of
a) 10⁴⁵
b) 10⁴²
c) 10⁵⁴
d) 10⁵¹
Answer:
a) 10⁴⁵
Solution:
Power P = En = \(\frac{\mathrm{hc}}{\lambda}\).n
n = \(\frac{P \lambda}{h c}\)
= \(\frac{3.8 \times 10^{26} \times 550 \times 10^{-9}}{6.6 \times 10^{-34} \times 3 \times 10^{8}}\)
= 105.5 × 10⁴³
n = 1.055 × 10⁴⁵

Question 11.
The threshold wavelength for a metal surface whose photoelectric work function is 3.313 eV is
a) 4125 Å
b) 3750 Å
c) 6000 Å
d) 2062.5 Å
Answer:
b) 3750 Å
Solution:
Φ = hν₀ = \(\frac{\mathrm{hc}}{\lambda_{\mathrm{o}}}\)

λ₀ = \(\frac{\mathrm{hc}}{\phi}\)
= \(\frac{6.64 \times 10^{-34} \times 3 \times 10^{8}}{500 \times 10^{-9}}\)
λ₀ = 3.757 × 10^-7
λ₀ = 3750 Å

Question 12.
Light of wavelength 500 nm is incident on a sensitive plate of photoelectric work function 1.235 eV. The kinetic energy of the photoelectrons emitted is (Take h = 6.6 × 10^-34 Js)
a) 0.58 eV
b) 2.48 eV
c) 1.24 eV
d) 1.16 eV
Answer:
c)1.24 eV
Solution:
λ = 500 nm;
φ = 1.235 eV
hν = \(\frac{\mathrm{hc}}{\lambda}\)

hν = \(\frac{6.64 \times 10^{-34} \times 3 \times 10^{8}}{500 \times 10^{-9}}\)
= 0.0396 × 10^-17
hν = 3.96 × 10^-19 J
hν = \(\frac{3.96 \times 10^{-19}}{1.6 \times 10^{-19}}\) = 2.475 evacuated
K.E = hν – φ
= 2.475 – 1.235
= 1.24 eV

Question 13.
Photons of wavelength λ are incident on a metal. The most energetic electrons ejected from the metal are bent into a circular arc of radius R by a perpendicular magnetic field having magnitude B. The work function of the metal is
a) \(\frac{\mathrm{hc}}{\lambda}-\mathrm{m}_{\mathrm{e}}+\frac{\mathrm{e}^{2} \mathrm{~B}^{2} \mathrm{R}^{2}}{2 \mathrm{~m}_{\mathrm{e}}}\)

b) \(\frac{\mathrm{hc}}{\lambda}+2 \mathrm{me}\left[\frac{\mathrm{eBR}}{2 \mathrm{~m}_{\mathrm{e}}}\right]^{2}\)

c) \(\frac{\mathrm{hc}}{\lambda}-\mathrm{m}_{\mathrm{e}} \mathrm{C}^{2} \frac{\mathrm{e}^{2} \mathrm{~B}^{2} \mathrm{R}^{2}}{2 \mathrm{~m}_{\mathrm{e}}}\)

d) \(\frac{\mathrm{hc}}{\lambda}-2 \mathrm{~m}_{\mathrm{e}}\left[\frac{\mathrm{eBR}}{2 \mathrm{~m}_{\mathrm{e}}}\right]^{2}\)
Answer:
d) \(\frac{\mathrm{hc}}{\lambda}-2 \mathrm{~m}_{\mathrm{e}}\left[\frac{\mathrm{eBR}}{2 \mathrm{~m}_{\mathrm{e}}}\right]^{2}\)
Solution:

Question 14.
The work functions for metals A, B and C are 1.92 eV, 2.0 eV and 5.0 eV respectively. The metals which will emit photoelectrons for radiation of wavelength 4100 Å is/are
a) A Only
b) both A and B
c) all these metals
d) none
Answer:
b) both A and B
Solution:
Energy in eV = \(\frac{12375}{\lambda}\)
\(\frac{12375}{4100}\) =3.01 eV
Work functions at A and B are less than 3.01 eV so both A and B emit.

Question 15.
Emission of electrons by the absorption of heat energy is called ________ emission
a) photoelectric
b) field
c) thermionic
d) secondary
Answer:
c) thermionic

II. Short Answer Questions:

Question 1.
Why do metals have a large number of free electrons?
Answer:
In metals, the electrons in the outermost shells are loosely bound to the nucleus. Even at room temperature, there are a large number of free electrons which are moving inside the metal in a random manner.

Question 2.
Define the work function of a metal. Give its unit.
Answer:

• The minimum energy needed for an electron to escape from the metal surface is called the work function of a metal.
• It is denoted by Φ₀ and its unit is eV

Question 3.
What is the photoelectric effect?
Answer:
The ejection of electrons from a metal plate when illuminated by light or any other electromagnetic radiation of suitable wavelength (or) frequency.

Question 4.
How does photocurrent vary with the intensity of the incident light?
Answer:
Photocurrent – the number of electrons emitted per second is directly proportional to the intensity of the incident light.

Question 5.
Give the definition of intensity of light and its unit.
Answer:

• The intensity is the power of light commonly referred to brightness.
• Its unit is candela (cd).

Question 6.
How will you define threshold frequency?
Answer:
For a given metallic surface, the emission of photoelectrons takes place only if the frequency of the incident light is greater than a certain minimum frequency called the threshold frequency.

Question 7.
What is a photocell? Mention the different types of photocells.
Answer:
photocells: Photoelectric cell or photocell is a device which converts light energy into electrical energy. It works on the principle of the photoelectric effect.
Types:

• Photo emissive cell
• Photovoltaic cell
• Photoconductive cell

Question 8.
Write the expression for the de Broglie wavelength associated with a charged particle of charge q and mass m, when it is accelerated through a potential V
Answer:

• De Broglie wavelength λ = \(\frac{\mathrm{h}}{\sqrt{2 \mathrm{qmv}}}\)
• Where q = ne, h= Planck’s constant

Question 9.
State de Broglie hypothesis.
Answer:
De Broglie’s hypothesis, all matter particles like electrons, protons, neutrons in motion are associated with waves.

Question 10.
Why we do not see the wave properties of a baseball?
Answer:
Since the momentum of a baseball is very low and the wavelength is of the order of 10^-34 m the wave properties cannot be seen in a baseball.

Question 11.
A proton and an electron have the same kinetic energy. Which one has a greater de Brogue wavelength? Justify.
Answer:
de-Broglie wavelength of the particle is λ = \(\frac { h }{ p }\) = \(\frac { h }{ \sqrt { 2mK } } \)
i.e. λ ∝ \(\frac { h }{ \sqrt { m } } \)
As m_e << m_p, so λ_e >> λ_p
Hence protons have greater de-Broglie wavelength.

Question 12.
Write the relationship of de Broglie wavelength \ associated with a particle of mass m in terms of its kinetic energy K.
1. De Broglie wavelength h h
λ = \(\frac{\mathrm{h}}{\mathrm{m} \cdot \mathrm{v}}\)
= \(\frac{\mathrm{h}}{\sqrt{2 \mathrm{emV}}}\)

2. Since kinetic energy of the electron K = eV then the de Broglie wavelength is given by
λ = \(\frac{\mathrm{h}}{\sqrt{2 \mathrm{mK}}}\)

Question 13.
Name an experiment which shows wave nature of the electron. Which phenomenon was observed in this experiment using an electron beam?
Answer:

• Davisson – Germer experiment confirmed the wave nature of electrons.
• They demonstrated that electron beams are diffracted when they fall on crystalline solids.

Question 14.
An electron and an alpha particle have same kinetic energy. How are the de Broglie wavelengths associated with them related?
Answer:
1. De Broglie wavelength is given by
λ = \(\frac{\mathrm{h}}{\sqrt{2 \mathrm{mK}}}\)
2. Since m_α > m_e
λ α \(\frac{1}{\sqrt{\mathrm{m}}}\) then
λ_α < λ_e
3. An α particle having a greater mass than electron so it is having lesser de Broglie wavelength.

III. Long Answer Questions:

Question 1.
What do you mean by electron emission? Explain briefly various methods of electron emission.
Answer:
The liberation of electrons from any surface of a metallic substance is called electron emission.
There are mainly four types of electron emission.
i) Thermionic emission:
1. When a metal is heated to a high temperature, the free electrons on the surface of the metal get sufficient thermal energy so that they are emitted from the metallic surface.
2. The intensity of the thermionic emission depends on the metal used and its temperature.
(Examples: Cathode ray tubes, electrons microscopes, X-ray tubes, etc.)

Electrons in the (a) metal (b) heated metal

ii) Field emission:
1. Electron field emission occurs when a very strong electric field is applied across the metal.
2. This strong field pulls the free electrons and helps them to overcome the surface barrier of the metal.
Examples:
Field emission scanning electron microscopes, Field emission display, etc….

Field emission

iii) Photoelectric emission :
1. When electromagnetic radiation of suitable frequency is incident on the surface of the metal, the energy is transferred from the radiation to the free electrons.
2. Hence the free electrons get sufficient energy to cross the surface barrier and the photoelectric emission takes place.
3. The number of electrons emitted depends on the intensity of the incident radiation.
Examples: Photodiodes, Photoelectric cells, etc.

Photoelectric emission

iv) Secondary emission:
1. When a beam of fast-moving electrons strikes the metal surface, the kinetic energy of the striking electrons is transferred to the free electrons on the metal surface.
2. Thus the free electrons get sufficient kinetic energy so that the secondary emission occurs.
Example: Image intensifiers, Photomultiplier tubes, etc..

Secondary emission of electrons

Question 2.
Briefly discuss the observations of Hertz, Hallwachs, and Lenard.
Answer:
Hertz Observation:
1. In 1887, Hertz generated and detected electromagnetic waves with his high voltage induction coil to cause a spark discharge between two metallic spheres.
2. When a spark is formed, the charges will oscillate back and forth rapidly and the electromagnetic waves are
produced.
3. The electromagnetic waves thus produced were detected by a detector that has a copper wire bent in the shape of a circle
4. But the tiny spark produced in the detecter cannot be explained by hertz.

Hallwach Observation:

Irradiation of ultraviolet light on

• uncharged zinc plate
• negatively charged plate
• positively charged plate

1. In 1888, Hallwach confirmed that the strange behaviour of the spark is due to the action of ultraviolet light.
2. A clean circular plate of zinc is mounted on an insulating stand and is attached to a gold leaf electroscope by a wire.
3. When the uncharged zinc plate is irradiated by ultraviolet light from an arc lamp, it becomes positively charged and the leaves will open.
4. If the negatively charged zinc plate is exposed to ultraviolet light, the leaves will close as the charges leaked away quickly.

Lenard’s observation:

1. In 1902, Lenard constructed an apparatus consists of two metallic plates A and C placed in an evacuated quartz bulb.
2. The Galvanometer G and battery B are connected in the circuit.
3. When ultraviolet light is incident there is a deflection in the galvanometer.
4. If anode A is exposed to ultraviolet light, no current is observed.
5. The electron emission observed when ultraviolet light falling on the negative plate called photoelectric emission.

Experimental setup for the study of the photoelectric effect

Question 3.
Explain the effect of potential difference on photoelectric current.
Answer:
1. The effect of potential difference on photoelectric current can be studied by keeping the frequency and the intensity of the incident light constant.

Variation of photocurrent with a potential difference

2. If the cathode is irradiated the potential of A is increased thereby increase in the photocurrent.
3. When all the photoelectrons from C are collected by A the photocurrent reaches a maximum called saturation current.
4. When a negative (retarding) potential is applied to A with respect to C the photoelectrons start to decrease because more and more photoelectrons are being repelled away.
5. The photocurrent becomes zero at a particular negative potential V₀ called stopping or cut off potential.
6. The negative potential applied to anode A which is just sufficient to stop the most energetic photoelectrons to make photocurrent zero is called stopping potential.
7. The kinetic energy of the fastest electron (K_max) is equal to the work done by the stopping potential to stop it (eV₀)
K_max = \(\frac{1}{2}\) mv_max² = eV₀ …………..(1)
where ν_max is the maximum speed of the photo electrons
ν_max = \(\sqrt{\frac{2 \mathrm{eV}_{\mathrm{o}}}{\mathrm{m}}}\)
= \(\sqrt{\frac{2 \times 1.602 \times 10^{-19}}{9.1 \times 10^{-31}} \times V_{\mathrm{O}}}\)
ν_max = 5.93 × 10⁵ \(\sqrt{\mathrm{V}_{\mathrm{O}}}\) …………….(2)
K_max = eV₀ (in Joule) or K_max = V₀ (in eV)
8. The maximum kinetic energy of the photoelectrons is independent of the intensity of the incident light.

Question 4.
Explain how the frequency of incident light varies with stopping potential.
Answer:
1. The effect of frequency of incident light on stopping potential can be studied by keeping the intensity of the incident light constant
2. The electrode potential varies for different frequencies of the incident light.
3. As the frequency is increased the photoelectrons are emitted with greater kinetic energies so that the retarding potential needed to stop the photoelectrons is also greater.

variation or photocurrent with corrector electrode potential for different frequencies of the incident radiation

4. From the graph between frequency and stopping potential, the stopping potential varies linearly with the frequency of the incident light.
5. The stopping potential is zero when no electrons are emitted below a certain frequency called threshold frequency.

Variation of stopping potential with frequency of the incident radiation for two metals

Question 5.
List out the laws of the photoelectric effect.
Answer:

1. For a given frequency of incident light, the number of photoelectrons emitted is directly proportional to the intensity of the incident light.
2. The maximum kinetic energy of the photoelectrons is independent of the intensity of the incident light.
3. The maximum kinetic energy of the photoelectrons from a given metal is directly proportional to the frequency of incident light.
4. For a given surface, the emission of photoelectrons takes place only if the frequency of incident light is greater than a certain minimum frequency called the threshold frequency.
5. There is no time lag between the incidence of light and emission of photoelectrons.

Question 6.
Explain Why the photoelectric effect cannot be explained on the basis of the wave nature of light.
Answer:
Failures of classical wave theory:
From Maxwell’s theory, light is an electromagnetic wave consisting of coupled electric and magnetic oscillations that move with the speed of light and exhibit typical wave behaviour. Let us try to explain the experimental observations of the photoelectric effect using wave picture of light.

1. When light is incident on the target, there is a continuous supply of energy to the electrons. According to wave theory, light of greater intensity should impart greater kinetic energy to the liberated electrons (Here, the Intensity of light is the energy delivered per unit area per unit time). But this does not happen. The experiments show that the maximum kinetic energy of the photoelectrons does not depend on the intensity of the incident light.

2. According to wave theory, if a sufficiently intense beam of light is incident on the surface, electrons will be liberated from the surface of the target, however low the frequency of the radiation is. From the experiments, we know that photoelectric emission is not possible below a certain minimum frequency. Therefore, the wave theory fails to explain the existence of threshold frequency.

3. Since the energy of light is spread across the wavefront, the electrons which receive energy from it are large in number. Each electron needs considerable amount of time (a few hours) to get energy sufficient to overcome the work function and to get liberated from the surface. But experiments show that photoelectric emission is almost instantaneous process (the time lag is less than 10“9 s after the surface is illuminated) which could not be explained by wave theory.

Question 7.
Explain the quantum concept of light.
Answer:
Planck’s concepts of quantum :

1. Max Planck proposed the quantum concept in 1900 in order to explain the thermal radiations emitted by a black body and the shape of the radiation curves.
2. If an oscillator vibrates with frequency ν, its energy can have only certain discrete values.
   E = nhν n = 1,2,3…………
3. Where h is Planck’s constant.
4. The oscillators emit or absorb energy in small packets or quanta and the energy of each quantum is E = hν
5. Energy is quantized and it is not continuous as believed in the wave nature. This is called the quantization of energy.

Einstein’s concept of quantum:

1. Einstein extended Planck’s quantum concept to explain the photoelectric effect in 1905.
2. According to Einstein, the energy in light is not spread out over wavefronts but is concentrated in small packets called energy quanta.
3. The light of frequency ν from any source having energy E = hν
4. The light quanta having the magnitude of linear momentum
   p = \(\frac{\mathrm{hv}}{\mathrm{c}}\)

Question 8.
Obtain Einstein’s photoelectric equation with the necessary explanation.
Answer:
When a photon of energy hν is incident on a metal surface, it is completely absorbed by a single electron and the electron is ejected. In this process, a part of the photon energy is used for the ejection of the electrons from the metal surface (photo electric work function Φ₀) and the remaining energy is imparted as kinetic energy of the ejected electron.
hν = Φ₀ + \(\frac{1}{2}\) mv² ………………….(1)
Where m is the mass and v is the velocity.
At threshold frequency, ν₀
There is no ejection of electrons hence zero kinetic energy then,
hν₀ = Φ₀ …………………(2)
eqn (1) => hν = hν₀ + \(\frac{1}{2}\) mv² ……………(3)
This is Einsteins photo electric equation.
If the electron does not lose energy by internal collisions, then it is emitted with maximum
kinetic energy K_max. Then
K_max = \(\frac{1}{2}\) mv_max²
Where ν_max maximum velocity of the electron ejected
K_max = hν – Φ₀ ……………..(4)

Emission of photoelectrons

A graph between K_max maximum kinetic energy of a photoelectron and frequency ν of the incident light is a straight line.

K_max vs ν graph

Question 9.
Explain experimentally observed facts of the photoelectric effect with the help of Einstein’s explanation.
Answer:

1. The experimentally observed facts of the photoelectric effect can be explained with the help of Einstein’s photoelectric equation.
2. As each incident photon liberates one electron, then the increase of intensity of the light (the number of per unit area per unit time) increases the number of electrons emitted thereby increasing the photocurrent.
3. From K_max = hν – Φ₀ it is evident that K_max is proportional to the frequency and independent of the intensity of the light.
4. From hν = hν₀ + \(\frac{1}{2}\) mv², there must be minimum energy equal to the work function of the metal to liberate electrons from the metal surface. Below which the emission of electrons is not possible.
5. There exists a minimum frequency called threshold frequency below which there is no photoelectric emission.
6. The transfer of photon energy to the electrons is instantaneous so that no time lag between the incidence of photons and ejection of electrons.
7. Thus the photoelectric effect is explained on the basis of the quantum concept of light.

Question 10.
Give the construction and working of a photoemissive cell.
Answer:
Photo emissive cell:
Construction:

Construction of photo cell

1. It consists of an evacuated glass or quartz bulb in which two metallic electrodes, cathode and anode are fixed.
2. The cathode C is Semi cylindrical in shape and is coated with a photo-sensitive material.
3. anode A is a thin rod or wire kept along the axis of the semi-cylindrical cathode.
4. A potential difference is applied between the anode and the cathode through a galvanometer G.

Working:
When cathode is illuminated, electrons are emitted from it. These electrons are attracted by anode and hence a current is produced which is measured by the galvanometer. For a given cathode, the magnitude of the current depends on (i) the intensity of incident radiation and (ii) the potential difference between anode and cathode.

Question 11.
Derive an expression for de Broglie wavelength of electrons.
Answer:
An electron of mass m is accelerated through a potential difference of V volt. The kinetic energy aquired by the electron is given by
\(\frac{1}{2}\) mv² = eV
Therefore, the speed ν of the electron is
ν = \(\sqrt{\frac{2 \mathrm{eV}}{\mathrm{m}}}\) …………..(1)
From de Broglie equation
λ = \(\frac{\mathrm{h}}{\mathrm{mv}}\) = \(\sqrt{\frac{\mathrm{h}}{2 \mathrm{emV}}}\) ……………(2)
Substituting the known values

When electron is accelerated with 100 V, then
λ = \(\frac{12.27}{\sqrt{100}}\) = 1.227 Å
Since the kinetic energy of the electron, K = eV, then the de Broglie wavelength associated with electron is given by
λ = \(\frac{\mathrm{h}}{\sqrt{2 \mathrm{mK}}}\) …………..(4)

Question 12.
Briefly explain the principle and working of an electron microscope.
Answer:
Principle:

(a) Optical Microscope
(b) Electron Microscope

1. The wave nature of the electron is used in the construction of an electron microscope.
2. The resolving power of a microscope is inversely proportional to the wavelength of the radiation used.
3. Since the de Broglie wavelength of the electron is much smaller than the visible light, the resolving power and the magnification are high.
4. Electron microscopes giving magnification more than 2,00,000 times than the optical microscope.

Working:

1. The construction and working of an electron microscope are similar to the optical microscope.
2. Focussing of electron beam is done by the electrostatic or magnetic lenses.
3. The divergence and convergence can be done by adjusting electric and magnetic fields.
4. The accelerated electrons from the source with high potential are made parallel by a magnetic condenser lens.
5. With the help of a magnetic objective lens and magnetic projector lens system, the magnified image is obtained.
6. These electron microscopes are being used in almost all branches of science.

Question 13.
Describe briefly Davisson – Germer experiment which demonstrated the wave nature of electrons.
Answer:

Experimental set up of Davisson – Germer experiment

1. De Broglie hypothesis of matter waves was experimentally confirmed by Clinton Davisson and Lester Germer in 1927.
2. They demonstrated that electron beams are diffracted when they fall on crystalline solids.
3. Since crystals can act as a three-dimensional diffraction grating for matter waves, the electron waves incident on crystals are diffracted off in certain specific directions.
4. The filament F is heated by a low tension battery, electrons are emitted from the hot filament by thermionic emission.
5. Electrons are accelerated due to-the potential between the filament and the anode aluminium cylinder by a high tension battery.
6. The electron beam is collimated and it is allowed to strike a single crystal of nickel by two thin aluminum diaphragms.
7. The electron detector measures the intensity of the scattered electron beam.
8. The intensity of the scattered beam is measured for various incident angles θ.
9. For accelerating voltage of 54 V, the scattered wave shows a peak at an angle of 50° to the incident beam.
10. The constructive interference of diffracted electrons for various atomic layers obtained known as interplanar spacing of Nickel.
11. The de-Broglie wavelength for V = 54 V is given by,

Variation of intensity of diffracted electron beam with the angle
λ = \(\frac{12.27}{\sqrt{\mathrm{V}}}\) Å
λ = \(\frac{12.27}{\sqrt{54}}\)
= 1.67 Å

IV. Numerical Problems:

Question 1.
How many photons per second emanate from a 50 mW laser of 640 nm?
Answer:
Given:
P = 50 × 10^-3 W
λ = 640 × 10^-9 m
N = ?
N => Number of photons emitted per second.

Question 2.
Calculate the maximum kinetic energy and maximum velocity of the photoelectrons emitted when the stopping potential is 81 V for the photoelectric emission experiment.
Answer:
Given:
V = 81 V
E_K = ?
E_K maximum kinetic energy
v_K maximum velocity
\(\frac{1}{2}\) mv² = eV
E_K = 1.6 × 10^-19 × 81
= 129.6 × 10^-19
E_K = 1.3 × 10^-17 J

Question 3.
Calculate the energies of the photons associated with the following radiation
(i) violet light of 413 nm,
(ii) X-rays of 0.1 nm,
(iii) radio waves of 10 m
Answer:
E = hν
E = \(\frac{\mathrm{hc}}{\lambda}\) in Joule

E = \(\frac{\mathrm{hc}}{\lambda \mathrm{e}}\) in eV
(i) Violet light of 413 nm
E = \(\frac{6.625 \times 10^{-34} \times 3 \times 10^{8}}{413 \times 10^{-9} \times 1.6 \times 10^{-19}}\)
= \(\frac{19.875}{660.8}\) × 10^-26 × 10²⁸
= 0.032 × 10²
E = 3 eV

(ii) X-rays of 0.1 nm
= \(\frac{6.625 \times 10^{-34} \times 3 \times 10^{8}}{0.1 \times 10^{-9} \times 1.6 \times 10^{-19}}\)

= \(\frac{19.875 \times 10^{-26}}{0.16 \times 10^{-28}}\)
= 124.24 × 10²
E = 12424 eV

(iii) radio waves of 10 m
E = \(\frac{6.625 \times 10^{-34} \times 3 \times 10^{8}}{10 \times 1.6 \times 10^{-19}}\)
= \(\frac{19.875}{1.6}\) × 10^-26 × 10^-1 × 10¹⁹
E = 1.24 × 10^-7 eV

Question 4.
A 150 W lamp emits light of mean wavelength of 5500 A. If the efficiency is 12%, find out the number of photons emitted by the lamp in one second.
Answer:
P = 150 W
λ = 5500 × 10^-10 m
Eff = 12%
N = \(\frac{\mathrm{P} \lambda}{\mathrm{hc}}\)

= \(\frac{150 \times 5500 \times 10^{-10}}{6.626 \times 10^{-34} \times 3 \times 10^{8}}\)

= \(\frac{825 \times 10^{-7}}{19.878 \times 10^{-26}}\)
= 41.5 × 10¹⁹
Number of photons emitted is with 12% efficiency = 41.5 × 10¹⁹ × \(\frac{12}{100}\)
N = 4.98 × 10¹⁹

Question 5.
How many photons of frequency 10¹⁴ Hz will make up 19.86 J of energy?
Answer:
E = 19.86 J
ν = 10¹⁴ Hz
E = nhν
n = \(\frac{E}{h v}\)
= \(\frac{19.86}{6.626 \times 10^{-34} \times 10^{14}}\)
= 2.997 × 10²⁰
Number of Photons N = 3 × 10²⁰

Question 6.
What should be the velocity of the electron so that its momentum equals that of 4000 Å wavelength photon.
Answer:
Given:
λ = 4000 × 10^-10 m

Question 7.
When a light of frequency 9 × 10¹⁴ Hz is incident on a metal surface, photoelectrons are emitted with a maximum speed of 8 × 10⁵ ms^-1. Determine the threshold frequency of the surface.
Answer:
Given:
ν = 9 × 10¹⁴ Hz
ν = 8 × 10⁵ms^-1
From Einstein’s photo electric equation
hν = hν₀ – \(\frac{1}{2}\) mv²
hν₀ = hν – \(\frac{1}{2}\) mv²
ν₀ = \(\frac{\mathrm{hv}-1 / 2 \mathrm{mv}^{2}}{\mathrm{~h}}\)
ν₀ = ν – \(\frac{\mathrm{mv}^{2}}{2 \mathrm{~h}}\)
= 9 × 10¹⁴ – \(\frac{9.1 \times 10^{-31} \times 64 \times 10^{10}}{2 \times 6.626 \times 10^{-34}}\)
= 9 × 10¹⁴ – \(\frac{582.4 \times 10^{-21}}{13.252 \times 10^{-34}}\)
= 9 × 10¹⁴ – 4.39 × 10¹⁴
= (9 – 4.39) × 10¹⁴
ν₀ = 4.61 × 10¹⁴ Hz

Question 8.
When a 6000 A light falls on the cathode of a photocell and produced photoemission. if a stopping potential of 0.8 V is required to stop the emission of an electron, then determine the
(i) frequency of the light
(ii) the energy of the incident photon
(iii) the work function of the cathode material
(iv) threshold frequency and
(v) the net energy of the electron after it leaves the surface.
Answer:
Given:
λ = 6000 × 10^-10 m;
eV₀ = 0.8 eV
i) ν = \(\frac{C}{\lambda}\)
= \(\frac{3 \times 10^{8}}{6 \times 10^{-7}}\)
= 0.5 × 10¹⁵
ν = 5 × 10¹⁴ Hz

(ii) E = hν
= \(\frac{6.626 \times 10^{-34} \times 5 \times 10^{14}}{1.6 \times 10^{-19}}\)
= \(\frac{53.13}{1.6}\) × 10^-20 × 10¹⁹
E = 2.07 eV

(iii) eν₀ = \(\frac{1}{2}\) mv² = 0.8 eV
W = hν – \(\frac{1}{2}\) mv²
= (2.07 – 0.8) eV
W = 1.27 eV

(iv) W = hν₀
ν₀ = \(\frac{1.27 \times 1.6 \times 10^{-19}}{6.626 \times 10^{-34}}\)
= \(\frac{2.032}{6.626}\) × 10¹⁵
ν₀ = 3.06 × 10¹⁴ Hz

(v) Net Energy = E = hν – hν₀
E = (2.07 – 1.27) ev = 0.8 eV
E = 0.8 eV

Question 9.
A 3310 Å photon liberates an electron from a material with energy 3 × 10^-19 J while another 5000 Å photon ejects an electron with energy 0.972 × 10^-19 J from the same material. Determine the value of Planck’s constant and the threshold wavelength of the material.
Answer:
Given:
λ₁ = 3310 × 10^-10 m
λ₂ = 5000 × 10¹⁰ m
K.E₁ = 3 × 10^-19 J
K.E₂ = 0.972 × 10^-19 J
i) ν₁ = \(\frac{C}{\lambda_{1}}\)
= \(\frac{3 \times 10^{8}}{3310 \times 10^{-10}}\)
= 9.06 × 10¹⁴ Hz
ν₂ = \(\frac{C}{\lambda_{2}}\)
= \(\frac{3 \times 10^{8}}{5000 \times 10^{-10}}\)
= 6 × 10¹⁴ Hz
hν₁ = W + K.E₁ …………….(1)
hν₁ = W + K.E₂ …………….(2)
eqn (1) – (2)
h(ν₁ – ν₂) = K.E₁ – K.E₂
h(9.06 – 6) × 10¹⁴ = 3 × 10^-19 – 0.972 × 10^-19
h(3.06 × 10¹⁴) = 2.028 × 10^-19
h = \(\frac{2.028 \times 10^{-19}}{3.06 \times 10^{14}}\)
= 0.662 × 10^-33
h = 6.62 × 10^-34 Js

ii)

Question 10.
At the given point of time, the earth receives energy from the sun at 4 cal cm min^-1. Determine the number of photons received on the surface of the Earth per cm^-2 per minute. (Given: Mean wavelength of sunlight = 5500 Å)
Answer:
Given:
E = 4 cal cm^-2 min^-1
λ = 5500 × 10^-10m
We know that 1 cal = 4.2 J
E = hnν

Number of photons n = 4.652 × 10¹⁹ per cm² per minute

Question 11.
UV light of wavelength 1800 Å is incident on a lithium surface whose threshold wavelength 4965 Å. Determine the maximum energy of the electron emitted.
Answer:
Given:
λ = 1800 × 10^-10 m
λ₀ = 4965 × 10^-10 m
hν = hν₀ +K.E
h\(\frac{c}{\lambda}\) =h\(\frac{c}{\lambda_{o}}\) + K. E
K.E = \(\frac{\mathrm{hc}}{\lambda}\) – \(\frac{\mathrm{hc}}{\lambda_{\mathrm{o}}}\)
hc = 6.625 × 10^-34 × 3 × 10⁸
hc = 19.86 × 10^-24
K.E = \(\frac{19.86 \times 10^{-26}}{1800 \times 10^{-10}}\) – \(\frac{19.86 \times 10^{-24}}{4965 \times 10^{-10}}\)
= 0.0110 × 10^-16 – 0.004 × 10^-16
K.E in eV = \(\frac{7 \times 10^{-19}}{1.6 \times 10^{-19}}\) = 4.375 eV
K.E = 4.4 eV

Question 12.
Calculate the de Brogue wavelength of a proton whose kinetic energy is equal to 81.9 x 1O’ J. (Given: mass of proton is 1836 times that of electron).
Answer:
Given:
K.E = 81.9 × 10^-15 J
m_p = 836 m_e

Question 13.
A deuteron and an alpha particle are accelerated with the same potential. Which one of the two has
i) greater value of de Broglie wavelength associated with it and
ii) less kinetic energy? Explain.
Answer:
Given:
deutron => e → 1e \(\left({ }_{1} \mathrm{H}^{2}\right)\)
m → 2m
alpha => e → 2e (2He⁴)
m → 4m
i)

ii) \(\frac{1}{2}\) mv² = eV
K_d = eV
K_α = 2 eV
K_α = 2 K_d
K_d = \(\frac{\mathrm{K}_{\alpha}}{2}\)

Question 14.
An electron is accelerated thorugh a potential difference of 81 V. What is the de Brogue wavelength associated with it? To which part of electromagnetic spectrum does this wavelength correspond?
Answer:
Given:
V = 81 V
λ = \(\frac{12.27}{\sqrt{\mathrm{V}}}\) Å
λ = \(\frac{12.27}{\sqrt{81}}\) ⇒ λ = \(\frac{12.27}{9}\)
λ = 1.36 Å

Question 15.
The ratio between the de Brogue wavelengths associated with protons. accelerated through a potential of 512 V and that of alpha particles accelerated through a potential of X volts is found to be one. Find the value of X.
Answer:
Given:
For proton charge = e
mass = m
For charge = 2e
mass = 4m

Part II:

12th Physics Guide Dual Nature of Radiation and Matter Additional Questions and Answers

I. Match the following:

Question 1.

Answer:
A. b
B. d
C. a
D. c

Question 2.

Answer:
A. b
B. c
C. d
D. a

Question 3.

Answer:
A. c
B. a
C. d
D. b

Question 4.

Answer:
A. d
B. c
C. b
D. a

II. Fill in the blanks:

Question 1.
The liberation of electrons from any surface of a substance is called _______.
Answer:
electron emission

Question 2.
1 eV is equal to ___________ Joule.
Answer:
1.602 × 10^-19

Question 3.
The stopping potential is independent of ________ of the incident light.
Answer:
intensity

Question 4.
The quality of X-rays is measured in terms of their _______.
Answer:
penetrating power

Question 5.
The graph between maximum kinetic energy of the photoelectron and frequency of the incident light is ________.
Answer:
straight line

Question 6.
Einstein’s photoelectric equation was experimentally confirmed by ________.
Answer:
Millikan

III. Choose the odd man out:

Question 1.
a) Field emission display
b) Photodiodes
c) Photomultiplier tubes
d) Electron microscope
Answer:
d) Electron MicroScope

Question 2.
a) Work function
b) Discharge tube
c) Threshold frequency
d) Stopping potential
Answer:
b) Discharge tube

Question 3.
a) mass
b) frequency
c) Intensity
d) wavelength
Answer:
a) mass

Question 4.
a) neutrons
b) tungsten
c) particles
d) x-rays
Answer:
a) tungsten

Question 5.
a) Photon
b) electron
c) proton
d) neutron
Answer:
a) photon

IV. Choose the incorrect pair:

Question 1.

Answer:
D) Intensity of X-rays – Constant for all substances

Question 2.

Answer:
D) Emission of photoelectrons – does not depend upon the potential of the electrodes

Question 3.

Answer:
B) Stopping potential – maximum potential between the electrodes

V. Choose the correct pair:

Question 1.

Answer:
B) de – Broglie wavelength – 1.67 Å

Question 2.

Answer:
D) V = \(\frac{\sqrt{2 \mathrm{em}}}{\mathrm{V}}\)

VI. Assertion and Reason:

Question 1.
Assertion:
The resolving power of the electron microscope is high.
Reason:
The wavelength of electrons is very much lesser than the visible light.
i) Assertion is true but reason is false
ii) The assertion and reason both are false
iii) Both assertion and reason are true and the reason is the correct explanation of the assertion.
iv) Both assertion and reason are true and the reason is not the correct explanation of the assertion.
Answer:
(iii) Both assertion and reason are true and the reason is the correct explanation of the assertion.

Question 2.
Assertion:
The oscillators emit or absorb energy in small packets or quanta.
Reason:
Energy is not discrete, the energy posses wave nature.
i) The assertion and reason both are false
i) The assertion is true but reason is false
iii) The assertion is false but reason is true
iv) Both the assertion and reason are true
Answer:
(ii) The assertion is true but the reason is false

VII. Choose the correct statement:
Question 1.
a) Particle cannot be localised in space and time
b) Wave can be localised in space and time
c) Black body radiation can be explained by wave nature.
d) The minimum energy needed for an electron to escape from the metal surface is called the work function.
Answer:
d) The minimum energy needed for an electron to escape from the metal surface is called the work function.

Question 2.
a) When the momentum of the particle increases de-Broglie wavelength also increases.
b) A photon of energy 2E is an incident on a photosensitive surface of photoelectric work function E. The maximum kinetic energy of photoelectron emitted is 2E.
c) The number of de-Broglie waves of an electron in the nth orbit of an atom is n.
d) The resolving power of the electron microscope is 100 times greater than an optical microscope.
Answer:
b) A photon of energy 2E is an incident on a photosensitive surface of photoelectric work function E. The maximum kinetic energy of the photoelectron emitted is 2E.

VIII. Choose the incorrect statement:

Question 1.
a) Wave mechanical concept of the atom was based on the de-Broglie hypothesis
b) Maximum kinetic energy of the photoelectrons varies linearly with the frequency of incident radiation.
c) The stopping potential of a metal surface is independent of the intensity of the incident radiation.
d) The graph drawn by taking the frequency of the radiation along the x-axis and stopping potential along the y-axis for a photo-sensitive metal is a parabola.
Answer:
d) The graph drawn by taking the frequency of the radiation along the x-axis and stopping potential along the y-axis for a photo-sensitive metal is a parabola.

Question 2.
a) Photoelectric emission is an instantaneous process.
b) Maximum kinetic energy of photoelectrons is directly proportional to the frequency of the incident radiation.
c) Maximum kinetic energy of photoelectrons is indirectly proportional to the intensity of the incident radiation.
d) Photoelectron emission is not possible below a minimum frequency of the incident radiation.
Answer:
c) Maximum kinetic energy of photoelectrons is indirectly proportional to the intensity of incident radiation.

IX. Choose the best answer:

Question 1.
The maximum kinetic energy of photoelectrons emitted from a surface when photons of
energy 3 eV fall on it is 4 eV. The stopping potential, in volt, is
(a) 2
(b) 4
(c) 6
(d) 10
Answer:
(b) 4
Hint:
Stopping potential, V₀ = \(\frac { { K }_{ max } }{ e } \) = \(\frac { 4eV }{ e }\) = 4v

Question 2.
The threshold frequency is constant with respect to _______.
a) type of the metal
b) Velocity of electrons
c) Voltage applied
d) intensity of the incident light.
Answer:
a) type of the metal

Question 3.
In a photoemissive cell, the anode is made up of _______.
a) copper
b) gold
c) platinum
d) zinc
Answer:
c) platinum

Question 4.
The work function of a substance is 4.0 eV. The longest wavelength of light that can cause photoelectron emission from this substance is approximately
(a) 540 nm
(b) 400 nm
(c) 310 nm
(d) 220 nm
Answer:
(c) 310 nm
Hint:
λ₀ = \(\frac { hc }{ W }\) = \(\frac{6.63 \times 10^{-34} \times 3 \times 10^{8}}{4.0 \times 1.6 \times 10^{-19}}\) = m = 310 x 10^-9 m = 310 nm

Question 5.
Duane-Hunt law is ________.
a) λ = \(\frac{12400}{\mathrm{v}}\) m
b) λ = \(\frac{\mathrm{hc}}{\mathrm{V}}\) m
c) λ = \(\frac{\mathrm{hc}}{\sqrt{\mathrm{E}_{\mathrm{k}}}}\) m
d) none of the above
Answer:
a) λ = \(\frac{12400}{\mathrm{v}}\) m

Question 6.
The resolving power of the electron microscope is _____ times greater than the resolving power of the optical
microscope
a) 10²
b) 10⁴
c) 10⁵
d) 10³
Answer:
c) c) 10⁵

Question 7.
4 eV is the energy of the incident photon and the work function is 2 eV. The stopping potential will be
(a) 2V
(b) 4V
(c) 6V
(d) 2√2V
Answer:
(d) 2√2V
Hint:
eV₀= hv- W₀ = 4eV – 2eV = 2eV
∴ V₀= \(\frac { 2ev }{ e }\) = 2v

Question 8.
Which of the following graph represents the variation of the particle momentum and associated de Broglie wavelength.
a)

b)

c)

d)
Answer:
c)

Question 9.
The radiation produced from decelerating electron is called ________.
a) reverse radiation
b) Photon emission
c) black body radiation
d) breaking radiation
Answer:
d) breaking radiation

Question 10.
If the striking electrons knocks of an electron in n = 2 state, the resulting transition give ________.
a) K-lines
b) L-lines
c) M-lines
d) N-lines
Answer:
b) L-lines

Question 11.
When a proton is accelerated through IV, then its kinetic energy will be
(a) 1 eV
(b) 13.6 eV
(c) 1840 eV
(d) 0.54 eV
Answer:
(a) 1 eV
Hint:
K = qV = e x 1V= 1 eV

Question 12.
The work function of a photoelectric material is 3.3 eV. The threshold frequency will be equal to
a) 8 × 10¹⁴ Hz
b) 8 × 10¹⁰ Hz
c) 5 × 10²⁰ Hz
d) 4 × 10¹⁴ Hz
Answer:
a) 8 × 10¹⁴ Hz
Solution:

Question 13.
The momentum of the electron having wavelength of 4 Å is
a) 1.6 × 10²⁴ kg ms^-1
b) 1.65 × 10^-24 kg ms^-1
c) 3.3 × 10²⁴ kg ms^-1
d) 3.3 × 10^-24 kg ms^-1
Answer:
b) 1.65 × 10^-24 kg ms^-1
Solution:
λ = \(\frac{\mathrm{h}}{\mathrm{p}}\)
p = \(\frac{h}{\lambda}\)
= \(\frac{6.6 \times 10^{-34}}{4 \times 10^{-10}}\)
p = 1.65 × 10^-24 kgms^-1

Question 15.
The number of photo-electrons emitted for the light of a frequency υ (higher than the threshold frequency υ₀) is proportional to
(a) Threshold frequency (υ₀)
(b) Intensity of light
(c) Frequency of light (υ)
(d) υ – υ₀
Answer:
(b) Intensity of light
Hint:
The photoelectric current of Intensity of incident light

Question 15.
The maximum kinetic energy of photoelectrons emitted in a photoelectric effect phenomenon is 3.2eV What is the value of stopping potential to stop the electrons not to reach the anode?
a) 1.6 eV
b) -3.2 eV
c) -1.6 eV
d) -6.4 eV
Answer:
b) -3.2 eV
Solution:
K.E_max = \(\frac{1}{2}\) mv²
V₀ = \(\frac{\mathrm{K} . \mathrm{E}}{e}\)
= \(\frac{3.2 \times 1.6 \times 10^{-19}}{1.6 \times 10^{-19}}\)
V₀ = -3.2 eV

Question 16.
Radiation of energy 6.2 eV is incident on the metal surface of work function 4.7eV. Find the kinetic energy of the
electrons emitted.
a) 3 × 10^-19 J
b) 1.6 × 10^-19 J
c) 2.4 × 10^-19 J
d) 3.2 × 10^-19 J
Answer:
c) 2.4 × 10^-19 J
Solution:
hν = 6.2 eV
W = 4.7 eV
\(\frac{1}{2}\) mv² = hν – W
= (6.2 – 4.7) eV
= 1.5 ev
= 1.5 × 1.6 × 10^-19
\(\frac{1}{2}\) mv² = 2.4 × 10^-19 J
K.E = 2.4 × 10^-19 J

Question 17.
The de-Broglie wavelength of electrons moving with a speed of 500 km/s
a) 1.45 nm
b) 1.45 Å
c) 1.45 m
d) 4.6 × 10²⁴ HZ
Answer:
a) 1.45 nm
Solution:
λ = \(\frac{\mathrm{h}}{\mathrm{mv}}\)
= \(\frac{6.6 \times 10^{-34}}{9.1 \times 10^{-31} \times 500 \times 10^{3}}\)
λ = 1.45 × 10^-19 ;
λ = 1.45 nm

Question 18.
Electron volt is a unit of
(a) Energy
(b) potential
(c) current
(d) charge
Answer:
(a) Energy
Hint:
An electron volt is a unit of energy

Question 19.
The work function of iron is 4.7 V. calculate the cut-off wavelength for this metal.
a) 2633 Å
b) 26.4 × 10^-7 m
c) 13.2 × 10^-10 m
d) 1320 Å
Answer:
a) 2633 Å
Solution:
hν₀ = W;
h\(\frac{\mathrm{C}}{\lambda_{0}}\) = W;
λ₀ = \(\frac{\mathrm{hc}}{\mathrm{W}}\)
= \(\frac{6.6 \times 10^{-34} \times 3 \times 10^{8}}{4.7 \times 1.6 \times 10^{-19}}\)
= 2633 × 10^-10
λ₀ = 2633 Å

Question 20.
The time taken by a photoelectron to come out after photon strikes is approximately
(a) 10^-14 s
(b) 10^-10 s
(c) 10^-16 s
(d) 10^-1 s
Answer:
(b) 10^-10 s
Hint:
The time lag between the incident of photon and the emission of photoelectrons is 10^-10 s approximately.

Question 21.
A Coolidge tube operates at 37200 V maximum frequency of x rays emitted is _______.
a) 9 × 10²⁸ Hz
b) 100 Hz
c) 9 × 10¹⁸ Hz
d) 3 × 10¹⁸ Hz
Answer:
c) 9 × 10¹⁸ Hz
Solution:

Question 22.
De – Broglie wavelength of an electron accelerating by 100 V
a) 1.227 Å
b) 122.7 μm
c) 0.2227 m
d) 12.27 Å
Answer:
a) 1.227 Å
Solution:
λ = \(\frac{12.27}{\sqrt{\mathrm{V}}}\)
= \(\frac{12.27}{\sqrt{100}}\)
= \(\frac{12.27}{10}\)
λ = 1.227 Å

Question 23.
The energy of photon of wavelength λ is
(a) \(\frac { hc }{ λ }\)
(b) hλc
(c) \(\frac { λ }{ hc }\)
(d) \(\frac { hλ }{ c }\)
Answer:
(a) \(\frac { hc }{ λ }\)
Hint:
E = hυ = \(\frac { hc }{ λ }\)

X. Two Mark Questions:

Question 1.
Why electron is preferred over X-ray in the microscope?
Answer:

1. The de-Broglie wavelength of an electron is very less compared to X-rays.
2. We can build a high resolving power microscope using electrons.
3. Resolving power of a microscope inversely proportional to the wavelength
   r₀ α \(\frac{1}{\lambda}\)

Question 2.
What are photoelectrons?
Answer:
These are the electrons emitted from a metal surface when it is exposed to electromagnetic radiations of a suitable frequency.

Question 3.
What are matter waves?
Answer:
The moving elementary particles behave as waves under suitable conditions. These waves associated with particles are called matter waves or de-Broglie waves.

Question 4.
What are continuous x rays?
Answer:
Continuous x-ray spectrum consists of radiations of all possible wavelengths from a certain lower limit to higher values continuously as in the case of visible light.

Question 5.
Why is a photo-cell also called an electric eye?
Answer:
Like an eye, a photo-cell can distinguish between weak and intense light. But a photocell gives a measure of light intensity in terms of photoelectric current. So it is also called an electric eye.

Question 6.
What is a photoemissive cell?
Answer:
Its working depends on the electron emission from a metal cathode due to irradiation of light and other radiation.

Question 7.
What are X-ray spectra?
Answer:
X-rays are produced when fast-moving electrons strike the metal target. The intensity of the X-rays when plotted against its wavelength gives a curve called X-ray spectrum.

Question 8.
What are photoconductive cells?
Answer:
The resistance of the semiconductor changes in accordance with the radiation energy incident on it.

Question 9.
Define resolving power of the microscope.
Answer:
The resolving power of a microscope is inversely proportional to the wavelength of the radiation used.

Question 10.
Who invented the particle nature of light?
Answer:
Hertz confirmed that the light is an electromagnetic wave. But the same experiment also produced the first evidence for particle nature of light.

Question 11.
Define intensity of light.
Answer:
Intensity denotes power of light means brightness.

Question 12.
What is diffraction?
Answer:
The bending of light waves round the edges of obstacles is called diffraction.

Question 13.
When light behaves like waves and matter?
Answer:
Light behaves as a wave during its propagation and behaves as a particle during its interaction with matter.

XI. Three Marks Questions:

Question 1.
What is nature of light?
Answer:
The wave nature of light explains phenomena such as interference, diffraction, and polarisation. Certain phenomenon like black body radiation and photoelectric effect light behaves as particles. Thus light posses dual nature, that is particle and wave.

Question 2.
Define one electron volt.
Answer:
One electron volt is defined as the kinetic energy gained by an electron when accelerated by a potential difference of 1 V.
1 eV = K.E gained by the electron or workdone by the electric field
1 eV = qv = 1.602 × 10^-19 C × 1 V
1 eV = 1.602 × 10^-19 J

Question 3.
Differentiate particle and wave.
Answer:
Particle is a material object which is considered as a tiny concentration of matter localized in space and time whereas wave is a broad distribution of energy not localized in space and time.

XII. Five Mark Questions:

Question 1.
What are the applications of the photocells?
Answer:

1. Photocells have many applications especially switches and sensors.
2. Automatic switching ON and OFF ordinary lights as well as street lights
3. They are used for the reproduction of sound in motion pictures.
4. Photocells are used as timers to measure the speeds of athletes during a race.
5. Photocells are used to measure the intensity of the given light and to calculate the exact time of exposure.

Question 2.
Write down the characteristics of photons.
Answer:
Characteristics of photons:
According to the particle nature of light, photons are the basic constituents of any radiation and possess the following characteristic properties:

• The photons of light of frequency v and wavelength λ will have energy, given by E = hυ = \(\frac { hc }{ λ }\).
• The energy of a photon is determined by the frequency of the radiation and not by its intensity and the intensity has no relation with the energy of the individual photons in the beam.
• The photons travel with the velocity of light and its momentum is given by p
• Since photons are electrically neutral, they are unaffected by electric and magnetic fields.
• When a photon interacts with matter (photon-electron collision), the total energy, total linear momentum, and angular momentum are conserved. Since photon may be absorbed or a new photon may be produced in such interactions, the number of photons may not be conserved

Question 3.
Write a note on characteristic X-rays. Give the applications of X-rays in medical therapy and industry.
Answer:
Characteristic X-ray Spectra:
1. X-ray spectra snow some narrow peaks at some, well-defined wavelengths when the target is hit by fast electrons. The line spectrum showing these peaks is called the characteristic X-ray spectrum.
2. When an energetic electron removes electrons from K-shell electrons then the electrons from the outer orbit jump to fill the vacancy.
3. Energy difference between the levels is given out as X-ray photon of definite wavelength.

Origin of characteristics X-ray Spectra

K-Series (K_α and K_β): This line is due to electronic transitions from L, M, and N shells to K-level.
L-Series (L_α and L_β): It arises due to electronic transitions from M, N, and O shells.

Uses of X-rays:

1. Medical diagnosis: used to detect fractures, foreign bodies, diseased organs, etc.
2. Medical therapy: To kill diseased tissues, they are employed to cure skin diseases, malignant tumors.
3. Industry: To check for flaws in welded joints, motor tires, tennis balls, and wood. At the customs post, they are used for the detection of contraband goods.
4. Scientific research: To study crystalline structure i.e. arrangement of atoms and molecules in crystals.

XIII. Conceptual Questions:

Question 1.
Are other particles, other than electrons having a wave nature?
Answer:
The particles like neutrons and alpha particles are also associated with waves. They undergo diffraction when they scattered by suitable crystals.

Question 2.
Why diffraction effects of ordinary light is very small?
Answer:
The wavelength of light is high compared to the spacing between the lattice planes so that the diffraction pattern of ordinary light is less pronounced.

Question 3.
Why crystals are used for three-dimensional grating?
Answer:
The wavelength of X-rays are in the order of 10^-10 m which is comparable to the spacing between the crystal lattice planes. Since the crystals can serve as three-dimensional grating.

XIV. Additional Problems:

Question 1.
Calculate the momentum and the de- Broglie wavelength of an electron with kinetic energy 25 eV.
Solution
i) Momentum of the electron:
p = \(\sqrt{2 \mathrm{mk}}\)
= \(\sqrt{2 \times 9.1 \times 10^{-31} \times 25 \times 1.6 \times 10^{-19}}\)
= \(\sqrt{728 \times 10^{-50}}\)
= 26.98 × 10^-25 kgms^-1

ii) de Broglie wavelength:
λ = \(\frac{\mathrm{h}}{\mathrm{p}}\)
= \(\frac{6.626 \times 10^{-34}}{26.98 \times 10^{-25}}\)
= 0.2455 × 10^-34 × 10²⁵
= 0.2455 ×10⁹
λ = 2.455 Å

Question 2.
Monochromatic light of frequency 6 x 10¹⁴ Hz is produced by a laser. The power emitted is 2 x 10^-3w.
(i) What is the energy of each photon in the light?
(ii) How many photons per second, on average, are emitted by the source?
Solution:
(i) Energy of each photon,
E = hυ = 6.6 x 10^-34 x 6 x 10¹⁴
E = 3.98 x 10^-19J
(ii) If N is the number of photons emitted per second by the source, then
Power transmitted in the beam = N x energy of each photon
P = N
N = \(\frac { P }{ E }\) = \(\frac{2 \times 10^{-3}}{3.98 \times 10^{-19}}\)
N = 5 x 10¹⁵ Photons per second.

Question 3.
A proton is moving at a speed of 0.900 times the velocity of light. Find the kinetic energy in Joules and Mev.
Answer:
Given:
ν = 0.9 × 3 × 10⁸ ms^-1
Mass of proton m = 1.6 × 10^-27 kg
K.E = \(\frac{1}{2}\) mv²
= \(\frac{1}{2}\) × 1.673 × 10^-27 × 2.7 × 2.7 × 10¹⁶
= \(\frac{6.098 \times 10^{-11}}{1.6 \times 10^{-19}}\)
= 3.811 × 10⁸ eV
K.E = 3.81 MeV

Question 4.
Calculate the momentum of an electron with kinetic energy 2 eV.
Answer:
Given:
K.E = 2 eV
p = \(\sqrt{2 \mathrm{mk}}\)
p = \(\sqrt{2 \times 9.1 \times 10^{-31} \times 2 \times 1.6 \times 10^{-19}}\)
p = 7.63 × 10^-25 kgms^-1

Question 5.
Calculate the cut-off wavelength and cut off frequency of X-rays from an X-ray tube of accelerating potential 20,000 V.
Answer:
The cut-off wavelength of the characteristic X-rays is
λ₀ = \(\frac{12400}{\mathrm{v}}\) Å = \(\frac{12400}{20000}\) Å
= 0.62 Å
The corresponding frequency is
ν₀ = \(\frac{c}{\lambda_{0}}\)
= \(\frac{3 \times 10^{8}}{0.62 \times 10^{-10}}\)
= 4.84 × 10¹⁸ Hz

Question 6.
What is the (a) momentum, (b) speed, and (c) de-Broglie wavelength of an electron with the kinetic energy of 120 eV.
Solution:
Kinetic energy, K.E = 120 eV = 120 x 1.6 x 10^-19
K = K.E = 1.92 x 10^-17 J
(a) Momentum of an electron, P = \(\sqrt { 2mK } \)
P = \(\sqrt{2 \times 9.1 \times 10^{-31} \times 1.92 \times 10^{-17}}\)
P = 5.91 x 10^-24 kg ms^-1
(b) Speed of an electron,
v = \(\frac { p }{ m }\) = \(\frac{5.91 \times 10^{-24}}{9.1 \times 10^{-31}}\) = 6.5 x 10⁶ kg ms^-1
(c) de-Broglie wavelength,
λ = \(\frac { h }{ p }\) = \(\frac{6.6 \times 10^{-34}}{5.91 \times 10^{-24}}\) = 1.117 x 10^-10 = 0.112 x 10^-9 m
λ = 0.112 nm

Tamilnadu State Board New Syllabus Samacheer Kalvi 11th Physics Guide Pdf Chapter 2 Kinematics Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 11th Physics Solutions Chapter 2 Kinematics

11th Physics Guide Kinematics Book Back Questions and Answers

Part – I:
I. Multiple choice questions:

Question 1.
Which one of the following Cartesian coordinate systems is not followed in physics?

Answer:

Question 2.
Identify the unit vector in the following _______.

Answer:

Question 3.
Which one of the following quantities cannot be represented by a scalar?
a) Mass
b) length
c) momentum
d) magnitude of the acceleration
Answer:
c) momentum

Question 4.
Two objects of masses m₁ and m₂ fall from the heights h₁ and h₂ respectively. The ratio of the magnitude of their momenta when they hit the ground is _______. (AIPMT 2012)

Answer:

Question 5.
If a particle has negative velocity and negative acceleration, it speeds _______.
a) increases
b) decreases
c) remains the same
d) zero
Answer:
a) increases

Question 6.
If the velocity is \(\overline{V}\) = \(2 \hat{i}+t^{2} \hat{j}-9 \hat{k}\) then the magnitude of acceleration at t = 0.5s is _______.
a) 1ms^-2
b) 2 ms^-2
c) zero
d) -1ms^-2
Answer:
a) 1ms^-2

Question 7.
If an object is dropped from the top of a building and it reaches the ground at t = 4s, then the height of the building is (ignoring air resistance) (g = 9.8ms^-2)
a) 77.3m
b) 78.4m
c) 80.5
d) 79.2m
Answer:
b) 78.4m

Question 8.
A ball is projected vertically upwards with a velocity v. It comes back to the ground in time t. Which v-t graph shows the motion correctly? (NSEP 00-01)

Answer:

Question 9.
If one object is dropped vertically downward and another object is thrown horizontally from the same height, then the ratio of vertical distance covered by both objects at any instant t is _______.
a) 1
b) 2
c) 4
d) 0.5
Answer:
a) 1

Question 10.
A bail is dropped from some height towards the ground. Which one of the following represents the correct motion of the ball?

Answer:

Question 11.
If a particle executes uniform circular motion in the XY plane in a clockwise direction, then the angular velocity is in _______.
a) +y direction
b) +z direction
c) -z direction
d) -x direction
Answer:
c) -z direction

Question 12.
If a particle executes uniform circular motion, choose the correct statement _______. (NEET 2016)
a) The velocity and speed are constant.
b) The acceleration and speed are constant.
c) The velocity and acceleration are constant.
d) The speed and magnitude of acceleration are constant
Answer:
d) The speed and magnitude of acceleration are constant

Question 13.
If an object is thrown vertically up with the initial speed u from the ground, then the time taken by the object to return back to the ground is _______.
(a) \(\frac{u^{2}}{2 g}\)
(b) \(\frac{u^{2}}{g}\)
(c) \(\frac { u }{ 2g }\)
(d) \(\frac { 2u }{ g }\)
Answer:
(d) \(\frac { 2u }{ g }\)

Question 14.
Two objects are projected at angles 30° and 60° respectively with respect to the horizontal direction. The range of two objects are denoted as R_30° and R_60° Choose the correct relation from the following
a) R_30° = R_60°
b) R_30° = 4R_60°
c) R_30° = R_{\(\frac { 60° }{ 2 }\)}
d) R_30° = 2R_60°
Answer:
a) R_30° = R_60°

Question 15.
An object is dropped in an unknown planet from a height of 50m, it reaches the ground in 2s. The acceleration due to gravity in this unknown planet is _______.
a) g = 20ms^-2
b) g = 25ms^-2
c) g = 15ms^-2
d) g = 30ms^-2
Answer:
b) g = 25ms^-2

II. Short Answer Questions:

Question 1.
Explain what is meant by the Cartesian coordinate system?
Answer:
At any given instant of time, the frame of reference with respect to which the position of the object is described in terms of position coordinates (x,y,z) is called “Cartesian coordinate system”.

If x, y, and z axes are drawn in an anticlockwise direction, then the coordinate system is called a right-handed Cartesian coordinate system.

Question 2.
Define a vector. Give Example.
Answer:
Vector is a quantity which is described by both magnitude and direction. Geometrically a vector is a directed line segment.
Example – force, velocity, displacement.

Question 3.
Define a Scalar. Give Examples.
Answer:
Scalar is a property of a physical quantity which can be described only by magnitude.
Example: Distance, Mass, Temperature, Speed, Energy, etc.

Question 4.
Write short note on the scalar product between two vectors.
Answer:
The Scalar product of two vectors (dot product) is defined as the product of the magnitudes of both the vectors and the cosine of angle between them.
If \(\vec{A}\) and \(\vec{B}\) are two vectors having an angle θ between them, then their scalar or dot product is

Example: W = \(\vec{F}\).\(\vec{dr}\). Work done is a scalar product of force \(\vec{F}\) and \(\vec{r}\)

Question 5.
Write a Short note on vector product between two vectors.
Answer:
The vector product or cross product of two vectors is defined as another vector having a magnitude equal to the product of the magnitudes of two vectors and the sine of the angle between them. The direction of the product vector is perpendicular to the plane containing the two vectors, in accordance with the right hand screw rule or right hand thumb rule. Thus, if\(\overrightarrow{\mathrm{A}}\) and \(\overrightarrow{\mathrm{B}}\) are two vectors, then their vector product is written as \(\overrightarrow{\mathrm{A}}\) × \(\overrightarrow{\mathrm{B}}\) which is a vector C defined by \(\overrightarrow{\mathrm{c}}\) = \(\overrightarrow{\mathrm{A}}\) x \(\overrightarrow{\mathrm{B}}\) = (AB sin 0) \(\hat{n}\)
The direction \(\hat{n}\) of \(\overrightarrow{\mathrm{A}}\) x \(\overrightarrow{\mathrm{B}}\) , i.e., \(\overrightarrow{\mathrm{c}}\) is perpendicular to the plane containing the vectors \(\overrightarrow{\mathrm{A}}\) and \(\overrightarrow{\mathrm{B}}\).

Question 6.
How do you deduce that two vectors are perpendicular?
Answer:
If the vector product of the two given vectors is having maximum magnitude.
i.e sinθ = 90°, [ (\(\vec{A}\) x \(\vec{B}\))Max = AB\(\hat{n}\) ] then the two vectors are said to be perpendicular.

Question 7.
Define Displacement and distance.
Answer:
Distance is the actual path length traveled by an object in the given interval of time during the motion. It is a positive scalar quantity. Displacement is the difference between the final and initial positions of the object in a given interval of time. It can also be defined as the shortest distance between these two positions of the object. It is a vector quantity.

Question 8.
Define velocity and speed.
Answer:
Velocity – Velocity is defined as the rate of change of position vector with respect to time (or) defined as the rate of change of displacement. It Is a vector quantity.

Speed – Speed is defined as the rate of change of distance. It is a scalar quantity.

Question 9.
Define acceleration.
Answer:
Acceleration is defined as the rate of change of velocity.
Acceleration \(\vec{a}\) = \(\frac{d \vec{v}}{d t}\)
Acceleration is a vector quantity.
Unit – ms^-2
Dimensional formula-[LT^-2]

Question 10.
What is the difference between velocity and average velocity?
Answer:

Question 11.
Define a radian.
Radian is defined as ratio of length of the arc to radians of the arc. One radian is the angle subtended at the center of the circle by an arc that is equal to in length to the radius of the circle.

Question 12.
Define angular displacement and angular velocity.
Answer:

1. Angular displacement: The angle described by the particle about the axis of rotation in a given time is called angular displacement.
2. Angular velocity: The rate of change of angular displacement is called angular velocity.

Question 13.
What is non-uniform circular motion?
Answer:
When an object is moving in a circular path with variable speed, it covers unequal distances in equal intervals of time. Then the motion of the object is said to be a non-uniform circular motion. Here both speed and direction during circular motion change.

Question 14.
Write down the kinematic equations for angular motion.
Answer:
The Kinematic equations for angular motion are ω = ω₀ + αt
θ = ω₀t + \(\frac { 1 }{ 2 }\)αt²
ω² = ω₀² + 2αθ
θ = \(\left(\frac{\omega_{0}+\omega}{2}\right)\) x t
ω₀ → initial angular velocity
ω → final angular velocity
α → angular acceleration
θ → angular displacement
t → time interval

Question 15.
Write down the expression for angle made by resultant acceleration and radius vector in the non-uniform circular motion.
Answer:
In the case of non-uniform circular motion, the particle will have both centripetal and tangential acceleration. The resultant acceleration is obtained as the vector sum of both centripetal and tangential acceleration.

This resultant acceleration makes an angle 6 with a radius vector, which is given by

III. Long Answer Questions:

Question 1.
Explain in detail the triangle law of addition.
Answer:
Let us consider two vector \(\vec{A}\) and \(\vec{B}\) as shown In fig.

Law: To find the resultant of two vectors, the triangular law of addition can be applied as follows.
A and B are represented as the two adjacent sides of a triangle taken in the same order. The resultant is given by the third side of the triangle taken in reverse order.

Magnitude of the resultant vector:
from figure
Let θ be the angle between two vectors.
from ∆ ABN, Sin θ = \(\frac { BN }{ AB }\) ⇒ ∴ BN = B sinθ
Cos θ = \(\frac { AN }{ AB }\) ⇒ ∴ AN = B Cos θ

Which is the magnitude of the resultant \(\vec{A}\) and \(\vec{B}\).

The direction of the resultant vector:
If \(\vec{R}\) makes an angle α with \(\vec{A}\) then

Question 2.
Discuss the properties of scalar and vector products.
Answer:
Properties of scalar product:
formula : \(\vec{A}\).\(\vec{B}\) = ABCosθ

1. The product quantity \(\overline{A}\).\(\overline{B}\) is always a scalar. It is positive if the angle between the vectors is acute (θ< 90°) and negative if angle between them is obtuse (90 < θ < 180)

2. The scalar product is commutative \(\overline{A}\).\(\overline{B}\) = \(\overline{B}\).\(\overline{A}\)

3. The scalar product obey distributive law. \(\overline{A}\).( \(\overline{B}\) + \(\overline{C}\) ) = \(\overline{A}\).\(\overline{B}\) + \(\overline{A}\).\(\overline{C}\)

4. The angle between the vector is θ = Cos^-1\(\frac{\bar{A} \cdot \bar{B}}{A B}\)

5. The scalar product of two vectors will be maximum when cos θ = 1 i.e θ = 0 ie when they are parallel.
[ ( \(\overline{A}\).\(\overline{B}\) ) max = AB.]

6. The scalar product of two vectors will be minimum when cos θ = -1 ie θ = 180°
( \(\overline{A}\).\(\overline{B}\))_mm = – AB [the vector are anti-parallel]

7. If two vector \(\overline{A}\) & \(\overline{B}\) are perpendicular to each other then \(\overline{A}\).\(\overline{B}\) = O. Because cos 90 = 0. Then vectors A & B are mutually orthogonal.

8. The scalar product of a vector with it self is termed as self or dot product and is given by
( \(\overline{A}\) )² = \(\overline{A}\).\(\overline{A}\) = AA cos θ = A²
Here 0=0
The magnitude or norm of the vector \(\overline{A}\) is
|A| = A = \(\sqrt{\bar{A} \cdot \bar{A}}\) = A.

9. Incase of orthogonal unit vectors
\(\hat{n}\).\(\hat{n}\) = 1 x 1cos0 = 1
for eg \(\hat{i}\).\(\hat{i}\) = \(\hat{j}\).\(\hat{j}\) = \(\hat{k}\).\(\hat{k}\) = 1

10. Incase of orthogonal unit vectors \(\hat{i}\), \(\hat{f}\), \(\hat{k}\) then \(\hat{i}\).\(\hat{j}\) = \(\hat{j}\).\(\hat{k}\) = \(\hat{k}\).\(\hat{j}\) = 1.1 cos 90 = 0.

11. In terms of components the scalar product of A and B can be written as

Properties of cross product:
Formula \(\vec{A}\) x \(\vec{B}\) = ABsinθ

1. The vector product of any two vectors is always an another vector whose direction perpendicular to the plane containing these two vectors, ie. Orthogonal to \(\overline{A}\) & \(\overline{B}\) even though \(\overline{A}\) & \(\overline{B}\) may not be mutually orthogonal.

2. Vector product is not commutative
\(\overline{A}\) x \(\overline{B}\) = – \(\overline{B}\).\(\overline{A}\)
\(\overline{A}\) x \(\overline{B}\) ≠ \(\vec{B}\) x \(\vec{A}\)
Here magnitude | \(\overline{A}\) x \(\overline{B}\) | = | \(\overline{B}\).\(\overline{A}\) | are equal but opposite direction.

3. The vector product of two vector is maximum when sine = 1, ie θ = 90°
ie. when \(\overline{A}\) and \(\overline{B}\) are orthogonal to each other.
( \(\overline{A}\) x \(\overline{B}\) ) max = AB \(\hat{n}\).

4. The vector product of two non zero vectors is minimum if |sinθ| = 0. ie. θ = 0 or 180°
( \(\overline{A}\) x \(\overline{B}\) ) m in = 0
Vector product of two non zero vectors is equal to zero if they either parallel or anti parallel

5. The self cross product ie product of a vector with itself is a null vector \(\overline{A}\) x \(\overline{B}\) = AA sinθ = 0

6. The self-vector product of the unit vector is zero
i.e. \(\hat{i}\).\(\hat{j}\) = \(\hat{j}\).\(\hat{j}\) = \(\hat{k}\).\(\hat{k}\) = 0

7. In case of orthogonal unit vectors \(\hat{i}\), \(\hat{j}\), \(\hat{k}\) in accordance with right hand cork screw rule \(\hat{i}\).\(\hat{j}\) =\(\hat{k}\), \(\hat{i}\).\(\hat{k}\) = \(\hat{i}\), \(\hat{k}\).\(\hat{i}\) = \(\hat{j}\) also since cross product is not commutative

9. If two vectors \(\overline{A}\) & \(\overline{B}\) form adjacent sides of a parallelogram then the magnitude of |\(\overline{A}\) x \(\overline{B}\)| will give area 0f parallelogram.

10. Since one can divide a parallelogram into two equal triangles, the area of the triangle is \(\frac { 1 }{ 2 }\) |\(\overline{A}\) x \(\overline{B}\)|.

Question 3.
Derive the kinematic equations of motion for constant acceleration.
Answer:
Consider an object moving in a straight line with uniform or constant acceleration ‘a’. Let u be the initial velocity at t = 0, and v be the final velocity after a time of t seconds

(i) Velocity time relation:
The acceleration of the body at any instant is given by first derivative of the velocity with time
a = \(\frac { dv }{ dt }\)
dv = adt
integrating both sides

Displacement time relation:

(ii) The velocity of the body is given by the first derivative of the displacement with respect to time
But v = ds/dt
∴ dv = v dt
v = u + at
ds = (u + at)dt
ds = udt + atdt
Integrating both sides

Velocity-displacement relation:

also we can derive from the relation v = u + at
v – u = at
Substituting in equation s = ut + \(\frac { 1 }{ 2 }\)at²

Question 4.
Derive the equations of motion for a particle (a) falling vertically (b) projected vertically.
Answer:
For a body falling vertically from a height ‘h’:
Consider an object of mass m falling from height h.
Neglecting air resistance, the downward direction as the positive y-axis.
The object experiences acceleration ‘g’ due to gravity which is constant near the surface of the earth.
In kinematic equations of motion \(\vec{a}\) = g\(\hat{i}\)
By comparing the components a_x = 0, a_g = 0, a_y= g

Case – 1
If the particle is thrown with initial velocity ‘u’ downward then
v = u + gt
y = ut + 1/2gt²
v² – u² = 2gy

Case – 2
Suppose the particle starts from rest,
u = 0
v = gt
y = 1/2gt²
v² = 2gy
For a body projected vertically: Consider an object of mass m thrown vertically upwards with an initial velocity u. Ne-glect air friction. The vertical direction as positive y axis then the acceleration,
a = – g
The kinematic equation of motion are v = u – gt
v = u – gt
s = ut – 1/2 gt²

Question 5.
Derive the equations of motion, range, and maximum height reached by a particle thrown at an oblique angle θ with respect to the horizontal direction.
Answer:
Consider an object thrown with an initial velocity u at an angle θ with horizontal.

Then initial velocity is resolved into two components
u_x = u cos θ horizontally and
u_y = u sin θ vertically
At maximum height u_y = 0 (since acceleration due to gravity is opposite to the direction of the vertical component).
The Horizontal component of velocity
u_x = u cos θ remains constant throughout its motion.
hence after the time t the velocity along the horizontal motion
V_x = U_x + a_xt
= ux = cos θ
The horizontal distance travelled by the projectile in a time ‘t’ is S_x = u_xt + 1/2 a_xt².
Here S_x = x u_x = u cos θ
a_x = 0
∴ x = u cos θt ____ (1)
∴ t = \(\frac { x }{ u cos θ }\) ____ (2)
For vertical motion
V_y = u_y + a_yt
Here v_y = v_y
u_y = u sin θ
a_y = – g
v_y = u sin θ – gt
The vertical distance travelled by the projectile in the same time ‘t’ is
S_y = U_y t + a_y t²
S_y = y, U_y = u sin θ a_y = – g
y = u sin θ t – 1/2 gt² ____ (4)
Substituting the value of t in (4) we get equation:

Which indicates the path followed by the projectile is an inverted parabola.

Expression for Maximum height:
The maximum vertical distance travelled by the projectile during its motion is called maximum height.
We know that
v_y² = u_y² + 2a_ys
Here u_y = u sin 0, a_y = – g, s = h_max
v_y = 0

Expression for horizontal range:
The maximum horizontal distance between the point of projection and the point on the horizontal plane where the projectile hits the ground is called horizontal range.
Horizontal range = Horizontal component of velocity x time of flight
R = u cos θ x t_f → (1)
Time of flight (t_f) is the time taken by the projectile from point of projection to point the projectile hits the ground again
w.k.t = S_y = u_y t_f + 1/2 a_y t²_f)
Here S_y = 0 u_y = u sin θ, a_y = – g
0 = u sin θ t_f – 1/2g t²_f
1/2 gt t²_f = u sin θ t_f

Question 6.
Derive the expression for centripetal acceleration.
Answer:
In uniform circular motion the velocity vector turns continuously with out changing its magnitude. ie speed remains constant and direction changes. Even though the velocity is tangential to every point is a circle, the acceleration it acting towards the centre of the circle along the radius. This is called centripetal acceleration

Expression:
The centripetal acceleration is derived from a simple geometrical relationship between position and velocity vectors. Let the directions of position and velocity vectors shift through same angle θ in a small time interval ∆t
For uniform circular motion r = \(\left|\bar{r}_{1}\right|\) = \(\left|\bar{r}_{2}\right|\)
and v = \(\left|\bar{v}_{1}\right|\) = \(\left|\bar{v}_{2}\right|\)
If the particle moves from position vector \(\bar{r}_{1}\) to \(\bar{r}_{2}\) the displacement is given by \(\overrightarrow{\Delta r}\) = \(\bar{r}_{2}\) – \(\bar{r}_{1}\)

and change in velocity from \(\bar{v}_{1}\) to \(\bar{v}_{2}\) is given ∆\(\bar { v }\) = \(\bar{v}_{2}\) – \(\bar{v}_{1}\)

The magnitudes of the displacement ∆r and ∆v satisfy the following relation

Here negative sign indicates that ∆v points radially inwards, towards the centre of the circle

For uniform circular motion v=rω where ω is the angular velocity of the particle about the center
The centripetal acceleration a = ω²r.

Question 7.
Derive the expression for total acceleration in the non-uniform circular motion.
Answer:
If the velocity changes both in speed and direction during circular motion, then we get non-uniform circular motion. Whenever the speed is not the same in a circular motion then the particle will have both centripetal and tangential acceleration.

The resultant acceleration is obtained by the vector sum of centripetal and tangential acceleration
Let the tangential acceleration be a_t.
Centripetal acceleration is v²/r.
The magnitude of the resultant acceleration is a_R = \(\sqrt{a_{t}^{2}+\left(\frac{v^{2}}{r}\right)^{2}}\)

IV. Exercises:

Question 1.
The position vector particle has a length of 1m and makes 30° with the x-axis what are the lengths of x and y components of the position vector?
Solution:

Question 2.
A particle has its position moved from \(\left|\bar{r}_{1}\right|\) = 3\(\hat{i}\) + 4\(\hat{j}\) to r\(\left|\bar{r}_{2}\right|\) = \(\hat{i}\)+ 2\(\hat{j}\) calculate the displacement vector ( ∆ \(\vec{r}\) ) and draw the \(\left|\bar{r}_{1}\right|\), \(\left|\bar{r}_{2}\right|\) and ( ∆ \(\vec{r}\) ) vector in a two dimensional Cartesian co-ordinate system.
Solution:

Question 3.
Calculate the average velocity of the particle whose position vector changes from \(\left|\bar{r}_{1}\right|\) = 5\(\hat{i}\) + 6\(\hat{j}\) to \(\left|\bar{r}_{2}\right|\) = 2\(\hat{i}\) + 3\(\hat{j}\) in a time 5 seconds.
Solution:

Question 4.
Convert the vector \(\overline{r}\) = 3\(\hat{i}\) + 2\(\hat{j}\) into a unit vector.
Solution:
A vector divided by its magnitude is a unit vector

Question 5.
What are the resultants of the vector product of two given vector given by
\(\overline{A}\) = 4\(\hat{i}\) – 2\(\hat{j}\) + \(\hat{k}\) and \(\overline{B}\) = 5\(\hat{i}\) + 3\(\hat{j}\) – 4\(\hat{k}\)?
Solution:

Question 6.
An object at an angle such that the horizontal range is 4 times the maximum height. What is the angle of projection of the object?
Solution:
Incase of obliging projection

Question 7.
The following graphs represent velocity-time graph. Identify what kind of motion a particle undergoes in each graph.

Solution:
(a) When the body starts from rest and moves with uniform acceleration is constant

(b) This graph represents, for a body moving with a uniform velocity or constant velocity. The zero slope of curve indicates zero acceleration.

(c) This v-t graph is a straight line not passing through origin indicates the body has a constant acceleration but greater than fig(i) as slope is more than the first one (more steeper)

(d) Greater changes in velocity (velocity variations are taking place in equal as travels of time. The graph indicates increasing acceleration.

Question 8.
The following velocity-time graph represents a particle moving in the positive x-direction. Analyse its motion from o to 7s calculate the displacement covered and distance traveled by the particle from 0 to 2s.

Solution:
From o to A(o to Is):
At t = os the particle has a zero velocity at t > 0 the particle has a negative velocity and moves in positive x-direction the slope dr/dt is negative. The particle is decelerating. Thus the velocity decreases during this time interval.

From A to B (Is to 2s):
From time Is to 2s the velocity increase and slope dv/dt becomes positive. The particle is accelerating. The velocity increases in this time interval.

From B to C (2s to 5s):
From 2s to 5s the velocity stays constant at 1 m/s. The acceleration is zero.

From C to D (6s to 7s):
From 5s to 6s the velocity decreases. Slope dv/dt is negative. The particle is decelerating. The velocity decreases to zero. The body comes to rest at 6s.

From D to E (6s to 7s)
The particle is at rest during this time interval.

Displacement: in 0 – 2s:
The total area under the curve from 0 to 2s displacement = 1/2bh + 1/2bh
=1/2 x 1.5 x (- 2) + 0.5 x 1
= – 1.5 + 0.25
= – 1.25 m

Distance: is 0 – 2s
The distance covered is = 1.5 + 0.25 = 1.75 m

Question 9.
A particle is projected at an angle of θ with respect to the horizontal direction. Match the following for the above motion.
(a) v_x – decreases and increases
(b) V_y – remains constant
(c) Acceleration – varies
(d) Position vector – remains downwards
Solution:
(a) V_x – remains constant
(b) V_y – decreases and increases
(c) Acceleration (a) – remains downwards
(d) Position vector (r) – varies

Question 10.
A water fountain on the ground sprinkles water all around it. If the speed of the water coming out of the fountains is V. Calculate the total area around the fountain that gets wet.
Solution :
Speed of water = V
(Range)_max = radius = u₂/g = v²/g
This range becomes the radius = (v²/g) of the circle where water sprinkled.
Area covered = Area of circle
= πr² = π\(\left(\frac{v^{2}}{g}\right)\)²
= π \(v^{4} / g^{2}\)

Question 11.
The following table gives the range of the particle when thrown on different planets. All the particles are thrown at the same angle with the horizontal and with the same initial speed. Arrange the planets in ascending order according to their acceleration due to gravity (g value)

Solution:
R = – (sin 2θ)
∵ the initial velocity and angle of projection are constants
R ∝ \(\frac { 1 }{ g }\)
g ∝ \(\frac { 1 }{ R }\)

According to acceleration, due to gravity In ascending order, the solution is. Mercury, Mars, Earth, Jupiter

Question 12.
The resultant of two vectors A and B is perpendicular to vector A and its magnitude is equal to half of the magnitude of vector B. Then the angle between A and B is
(a) 30°
(b) 45°
(c) 150°
(d)120°
Solution:
Let two vectors be A & B

Magnitude of B = B
Magnitude of A = A
∝ = 90°
Given:

Question 13.
Compare the components for the following vector equations.
(a) T\(\hat{j}\) – mg\(\hat{j}\) = ma\(\hat{j}\)
(b) \(\overline{T}\) + \(\overline{F}\) = \(\overline{A}\) + \(\overline{B}\)
(c) \(\overline{T}\) – \(\overline{F}\) = \(\overline{A}\) – \(\overline{B}\)
(d) T\(\hat{j}\) + mg\(\hat{j}\) = ma\(\hat{j}\)
Solution:
We can resolve all vectors in x, y, z components w.r.t. Cartesian co-ordinate system. After resolving the components separately equate x components on both sides y components on both sides and z components on both side we get.
(a) T\(\hat{j}\) – mg\(\hat{j}\) = ma\(\hat{j}\)
T – mg = ma

(b) \(\overline{T}\) + \(\overline{F}\) = \(\overline{A}\) + \(\overline{B}\)
T_x + F_x = A_x + B_x

(c) \(\overline{T}\) – \(\overline{F}\) = \(\overline{A}\) – \(\overline{B}\)
T_x – F_x = A_x – B_x

(d) T\(\hat{j}\) + mg\(\hat{j}\) = ma\(\hat{j}\)
T + mg = ma

Question 14.
Calculate the area of the triangle for which two of its sides are given by the vectors \(\overline{A}\) = 5\(\hat{i}\) – 3\(\hat{j}\) \(\overline{B}\) = 4\(\hat{i}\) + 6\(\hat{j}\).
Solution:

Question 15.
If the earth completes one revolution in 24 hours, what is the angular displacement made by the earth in one hour? Express your answer in both radian and degree.
Solution:
ω = θ/t θ = wt
In 24 hours, angular displacement made
θ = 360° (or) 2π rad
In 1 hours, angular displacement
θ = \(\frac { 360° }{ 24 }\)
θ = 15°
In radian θ = \(\frac { 2π }{ 24 }\) = \(\frac { π }{ 12 }\) radians.
θ = \(\frac { π }{ 12 }\) rad.

Question 16.
An object is thrown with initial speed of 5ms^-1 with an angle of projection of 30°. What is the height and range reached by the particle?
Solution:
u = 5 m/s
θ = 30°
h_max = ?
R = ?
Height reached

Range:

Question 17.
A football player hits the ball with a speed 20m/s with angle 30° with respect to as shown in the figure horizontal directions. The goal post is at a distance of 40 m from him. Find out whether the ball reaches the goal post.

Solution :
In order to find whether the ball is reaching the goal post the range should be equal to 40m so range

= \(\frac { 692.8 }{ 19.6 }\)
= 35.35 m.
Which is less than the distance of the goal post which is 40 m away so the ball won’t reach the goal post.

Question 18.
If an object is thrown horizontally with an initial speed 10 ms^-1 from the top of a building of height 100 m. What is the horizontal distance covered by the particle?
Solution:
u = 10 m/s
h = 100 m
x = ?
x = u x T

x = 45.18 m.

Question 19.
An object is executing uniform circular motion with an angular speed of π/12 radians per second. At t = 0 the object starts at an angle θ = 0. What is the angular displacement of the particle after 4s?
Solution :
ω = π/12 rad/s
ω = θ/t
θ = w x t = π/12 x 4
θ = π/3 radian
θ = \(\frac { 180° }{ 3 }\)
= 60°

Question 20.
Consider the x-axis as representing east, the y-axis as north, and the z-axis as vertically upwards. Give the vector representing each of the following points.

(a) 5m northeast and 2m up.
(b) 4m southeast and 3m up.
(c) 2m northwest and 4m up.
Solution:
5m northeast and 2m up.
(a) The vector representation of 5m N-E and 2m up is (5i + 5j) Cos 45° + 2\(\hat{k}\)

(b) 4m south east and 3m up.

The vector representing 4m south east and 3m up is
(4i – 4j) cos 45 + 3\(\hat{k}\)
\(\frac{4(i-j)}{\sqrt{2}}\) + 3\(\hat{k}\)

(c) 2m north west and 4m up.

The vector representing 2m northwest and 4m up

Question 21.
The moon is orbiting the earth approximately once in 27 days. What is the angle transversed by the moon per day?
Solution :
Angle described in 27 days = 2π rad = 360° days
Angie described in one day = 2π/27 radian
= \(\frac { 360° }{ 27 }\)
θ = 13.3°

Question 22.
An object of mass m has an angular acceleration ∝ = 0.2 rad/s². What is the angular displacement covered by the object after 3 seconds? (Assume that the object started with angle zero with zero angular velocity)
Solution:
∝ = 0.2 rad/s²
θ = ? t = 3s.
w₀ = 0
w.k.T θ = ω₀t + 1/2 ∝ t²
θ = 0 + 1/2 x 0.2 x 9
θ = 0.9 rad
θ = 0 = 0.9 x 57.295° = 51°
The magnitude of the resultant vector R is given by

11th Physics Guide Kinematics Additional Important Questions and Answers

I. Multiple choice questions:

Question 1.
A particle moves in a circle of radius R from A to B as in the figure.

Answer:

Question 2.
The branch of mechanics which deals with the motion of objects without taking force into account is –
(a) kinetics
(b) dynamics
(c) kinematics
(d) statics
Answer:
(c) kinematics

Question 3.
A particle moves in a straight line from A to B with speed v₁ and then from B to A with speed v₂. The average velocity and average speed are _______.

Answer:

Question 4.
A particle is moving in a straight line under constant acceleration. It travels 15m in the 3^rd second and 31m in the 7^th second. The initial velocity and acceleration are _______.
a) 5 m/s, 4 m/s²
b) 4 m/s, 5 m/s²
c) 4 m/s, 4 m/s²
d) 5 m/s, 5 m/s²
Answer:
a) 5 m/s, 4 m/s²

Question 5.
If an object is moving in a straight line then the motion is known as –
(a) linear motion
(b) circular motion
(c) curvilinear motion
(d) rotational motion
Answer:
(a) linear motion

Question 6.
A car is moving at a constant speed of 15 m/s. Suddenly the driver sees an obstacle on the road and takes 0.4 s to apply the brake. The brake causes a deceleration of 5 m/s². The distance traveled by car before it stops _______.
a) 6 m
b) 22.5 m
c) 28.5 m
d) 16.2 m
Answer:
c) 28.5 m

Question 7.
A car accelerates from rest at a constant rate for some time after which it decelerates at a constant rate (3 to come to rest. If the total time lapses in ‘t’ seconds, then the maximum velocity reached is _______.

Answer:

Question 8.
Spinning of the earth about its own axis is known as –
(a) linear motion
(b) circular motion
(c) curvilinear motion
(d) rotational motion
Answer:
(d) rotational motion

Question 9.
A particle is thrown vertically up with a speed of 40m/s, The velocity at half of the maximum height _______.
a) 20 m/s
b) 20\(\sqrt{2}\)m/s
c) 10 m/s
d) 10\(\sqrt{2}\)m/s
Answer:
b) 20\(\sqrt{2}\)m/s