(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) Why is the Solar Cooker box covered with a plane glass plate?
(b) Why is energy of water flowering in a river considered to be an indirect form of solar energy?
(c) How is the fission of nucleus brought about?

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)

Which is the process used to harness nuclear energy these days? Explain it briefly.

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)

a) Why is there a need for harnessing non-conventional sources of energy?
b) How can energy be harnessed from the sea in different ways?

5

(a)

What are the environmental consequences of using fossil fuels? Suggest the steps to minimize the pollution caused by various source of energy including non-conventional sources of energy?

5

(a)

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

5

(a)

(i) Write the value of solar constant of Sun.
(ii) What type of mirror is used in Box Type Solar Cooker?
(iii) Why it is difficult to use hydrogen as a source of energy?
(iv) Fossil fuels are classified as non-renewable source of energy. Explain why.

5

(a)

(i) Distinguish between renewable and non-renewable sources of energy giving one example of each.
(ii) Why is the use of wood as a fuel not advised although forests can be replenished?

5

(a)