I. Choose the correct Answer:<\/span><\/p>\nQuestion 1.
\nWhen diesel is burnt chemical energy is converted into _______.
\na) wind energy
\nb) heat energy
\nc) solar energy
\nd) sound energy
\nAnswer:
\nb) heat energy<\/p>\n
<\/p>\n
Question 2.
\nRunning water possesses _______.
\na) potential energy
\nb) chemical energy
\nc) kinetic energy
\nd) sound energy
\nAnswer:
\nc) kinetic energy<\/p>\n
Question 3.
\nUnit of energy is _______.
\na) Kilogram
\nb) Newton
\nc) Kelvin
\nd) Joule
\nAnswer:
\nd) Joule<\/p>\n
Question 4.
\nWhich one of the following requires wind energy?
\na) Bicycle
\nb) Photosynthesis
\nc) Parachute
\nd) Automobiles
\nAnswer:
\nc) Parachute<\/p>\n
Question 5.
\nCow dung possesses _______ .
\na) kinetic energy
\nb) chemical energy
\nc) solar energy
\nd) heat energy
\nAnswer:
\nb) chemical energy<\/p>\n
<\/p>\n
II. Find out the energy conversion that takes place in the following:<\/span><\/p>\nQuestion 1.
\nIron box: _______.
\nAnswer:
\nChemical energy to Heat energy<\/p>\n
Question 2.
\nElectric Iron box: _______.
\nAnswer:
\nElectric energy to Heat energy<\/p>\n
Question 3.
\nElectric fan:
\nAnswer:
\nElectric energy to Mechanical energy<\/p>\n
Question 4.
\nSpeaker:
\nAnswer:
\nElectric energy to Sound energy<\/p>\n
Question 5.
\nGenerator: _______.
\nAnswer:
\nMechanical energy to Electrical energy<\/p>\n
<\/p>\n
III. Find out form of energy possessed by the following things:<\/span><\/p>\nQuestion 1.
\nA rock on the top of a hill.
\nAnswer:
\nPontential Energy<\/p>\n
Question 2.
\nA rolling ball.
\nAnswer:
\nKinetic Energy<\/p>\n
Question 3.
\nCharcoal.
\nAnswer:
\nHeat Energy<\/p>\n
Question 4.
\nWater falls.
\nAnswer:
\nKinetic Energy<\/p>\n
Question 5.
\nBattery.
\nAnswer:
\nChemical Energy<\/p>\n
<\/p>\n
IV. Match the following:<\/span><\/p>\n
\nAnswer:<\/p>\n
\n- e<\/li>\n
- d<\/li>\n
- a<\/li>\n
- c<\/li>\n
- b<\/li>\n<\/ol>\n
<\/p>\n
V. Say True or False:<\/span><\/p>\nQuestion 1.
\nAn apple falling from a tree is an example for kinetic energy.
\nAnswer:
\nTrue<\/p>\n
Question 2.
\nElectrical energy is used to run electric trains.
\nAnswer:
\nTrue<\/p>\n
Question 3.
\nHeat energy cannot be produced by friction.
\nAnswer:
\nFalse<\/p>\n
Question 4.
\nPotential energy and heat energy are the two forms of mechanical energy.
\nAnswer:
\nFalse<\/p>\n
Question 5.
\nThe unit of energy is joule.
\nAnswer:
\nTrue<\/p>\n
<\/p>\n
VI. Answer in brief:<\/span><\/p>\nQuestion 1.
\nWhat is energy?
\nAnswer:
\nEnergy is defined as capacity to do work. S.I unit of work is Joule.<\/p>\n
Question 2.
\nWhat are the different forms of energy?
\nAnswer:
\nThere are different forms of energy like mechanical energy, heat energy, light energy, wind energy, solar energy, electrical energy, and chemical energy.<\/p>\n
Question 3.
\nWhat are the uses of mechanical energy?
\nAnswer:<\/p>\n
\n- In hydroelectric plants, kinetic energy of water is converted into electrical energy.<\/li>\n
- Windmills convert kinetic energy of winds into electrical energy.<\/li>\n
- Mechanical energy of the hammer is used to apply a force on a nail.<\/li>\n
- Mechanical energy can bring a moving body to rest and make a body at rest to move.<\/li>\n<\/ul>\n
Question 4.
\nState the Law of conservation of energy.
\nAnswer:
\nLaw of conservation of energy states that energy Can neither be created nor be destroyed. One form of energy is converted into another form of energy.<\/p>\n
Question 5.
\nGive the uses of Light energy.
\nAnswer:<\/p>\n
\n- We are able to see objects with the help of light energy.<\/li>\n
- Plants use light energy to synthesis their food.<\/li>\n
- With the help of light energy, our skin is able to synthesis Vitamin D.<\/li>\n
- Electricity can be produced with the help of light energy.<\/li>\n<\/ul>\n
<\/p>\n
VII. Answer in detail:<\/span><\/p>\nQuestion 1.
\nExplain the types of Mechanical energy.
\nAnswer:
\nEnergy possessed by an object due its position is called mechanical energy.
\nMechanical energy can be classified into two;<\/p>\n
\n- Kinetic energy<\/li>\n
- Potential energy<\/li>\n<\/ul>\n
a) Kinetic energy: Energy possessed by a moving objectis known as kinetic energy. It is also known as energy of motion.
\nEg: Moving car, cricket ball bowled by a player, bullet coming out of a gun.<\/p>\n
b) Potential energy: Energy possessed by an object which is at rest is known as potential energy. It is also known as stores energy of position.
\nEg: Object lifted above, stone in the stretched rubber, water in the dam.<\/p>\n
Question 2.
\nExplain Conservation of energy.
\nAnswer:
\nEnergy cannot be created cannot be destroyed also. It is changed from one form to another form or transferred from one object to another object. Examples for conservation of energy in our daily life are :<\/p>\n
1. Water dam :<\/p>\n