A solar water heater cannot be used to get hot water on

1

(a)

A sunny day

(b)

A cloudy day

(c)

A hot day

(d)

A windy day

In a hydro power plant

1

(a)

Potential energy possessed by stored water is converted into electricity.

(b)

Kinetic energy possessed by stored water in converted into potential energy.

(c)

Electricity is extracted form water.

(d)

Water is converted into steam to produce electricity.

Which part of the solar cooker is responsible for greenhouse effect?

1

(a)

Coating with black colour inside the box

(b)

Mirror

(c)

Glass sheet

(d)

Outer cover of the solar cooker

Choose the correct statement?

1

(a)

Sun can be taken as an inexhaustible source of energy

(b)

There is infinite storage of fossil fuels inside the earth.

(c)

Hydro and wind energy plants are nonpolluting sources of energy.

(d)

Waste from a nuclear power plant can be easily disposed off.

Choose the incorrect statement

1

(a)

We are encouraged to plant more trees so as to ensure clean environment and also provide biomass fuel.

(b)

Gobar-gas is produced when crops. vegetable wastes etc., decomposes in the absence of oxygen.

(c)

The main ingredient of biogas is ethane and it gives a lot of smoke and also produces a lot of residual ash.

(d)

Biomass is a renewable source of energy

Which one of the following is a renewable resource?
Natural gas, Petrroleum, Ground water, Coal

1

(a)

Among natural gas, petroleum, ground water and coal, only ground water is a renewable resource. It returns in the water cycle.

What is meant by the 'calorific value' of a fuel? How is it determined? Arrange the following fuels in a decreasing order of their calorific values: Kerosene, Coal, LPG.

1

(a)

The amount of heat produced in burning the unit mass of a fuel completely is known as the calorific value of that fuel. It is determined with the help of Bomb Calorimeter.
Arrangement of the fuels in a decreasing order of their calorific values.
LPG > Kerosene > Coal

What is energy?

1

(a)

Energy is the capability to do work.

What are fossil fuels?

1

(a)

Fuels which are formed from the fossil remains of plants and animals and are obtained from under the earth's crust are called fossil fuels. Example coal, petroleum and natural gas.

What is renewable source of energy?

1

(a)

A source of energy that can be obtained on a regular basis even after using it continuously is called renewable source of energy like solar, wind and water energy.

What is a good source of energy?

2

(a)

If you should use any source of energy for heating your food which one would you use and why?

2

(a)

Why are we looking at alternate sources of energy?

2

(a)

What is geometry energy?

2

(a)

Hydrogen has been used as a rocket fuel. Would you consider it a cleaner fuel then CNG? Why or why not?

2

(a)

Compare and contrast fossil fuels and the Sun as direct sources of energy.

2

(a)

What are the advantages and disadvantages of using a solar cooker? Are there places where solar cookers would have limited utility?

2

(a)

(a) Why is there a need to harness non-conventional source of energy?
(b) Give two main examples.

2

(a)

Mention three advantages of a solar cell.

2

(a)

Name the type of nuclear reaction by which the Sun produces its energy. List two conditions which are present at the centre of the Sun responsible for this reaction.

2

(a)

(a) What is a 'solar cell'?
(b) Why is biogas considered an ideal fuel for domestic use?
(c) Name a device in which controlled chain reaction is used.

5

(a)

(a) State one limitation of solar energy available from solar cells.
(b) What is the minimum wind velocity required to obtain useful energy with a windmill?
(c) Define the term 'nuclear fission'.

5

(a)

a) How can solar energy be harnessed?
b) Mention any two limitations in using solar energy.
c) How are these limitations overcome?

5

(a)

Energy from various sources is considered to have been derived from the sun. do you agree? Justify your answer.

5

(a)