Q. 2. Astrologers' perceptions are based on hearsay and conjecture tnat
they learn from the study of the stars. Comment with the reference to the story
Answers
Answer:
1.Name any two fossil fuels.
2. Mention the purpose of blackening the interior of a solar cooker.
3. List any three ways in which construction of dams for production of electricity adversely affects the environment of that
place.
4. Bio gas is an excellent fuel. Justify the statement by giving two reasons. Mention the main constituents of bio gas along
with its percentage.
5. (a) Define tidal energy.
(b) Explain how the tidal energy is harnessed and write one limitation of the use of tidal energy.
6. Define process of nuclear fission. Writ the steps involved in generating electricity in a nuclear reactor.
7. Solar cooker takes more time as compared to the LPG to boil potato or rice, yet Kunal uses solar cooker for such type
of cooking:
(i) Why does Kunal uses Solar cooker instead of LPG? Give reasons for your answer.
(ii) Name the phenomenon which is responsible for obtaining high temperature in solar cooker.
8. Name the part of a biogas plant where reactions take place in the absence of oxygen.
9. Name the kind of energy possessed by wind and the device used to harness it.
10. List two non-conventional sources of energy.
11. A black surface absorbs more heat radiations as compared to a white or a reflecting surface under identical
conditions. List two solar devices which make use of this property in their design.
12. Why a solar cooker painted black form outside?
13. Define fuel. List any two characteristics that you would look for in a good fuel.
14 State any three reasons to justify that LPG is considered as an ideal fuel.
15 Sate any three advantages of charcoal over wood.
16. What is acid rain?
17. Write the name of the substance whose vapours are used to run the turbine of the generator of ocean thermal energy
plant.
18. Mention the minimum temperature difference required between surface water and water at a depth of upto 2 km in an
ocean thermal energy plant.
19. Distinguish between renewable and non-renewable sources of energy. Also give an example of each of these
sources.
20. State the principle of working of ocean thermal energy conversion plant. Explain how the plant works? Write one
essential condition for it to operate properly.
21.Name one fuel used in nuclear reactor.
22.Name any two elements that are used in fabricating solar cells.
23.Name the reaction responsible for large energy production in the sun.
24.Mention why is it not possible to make use of solar cells to meet all our energy needs? State three reasons to support
your answer. Also mention three uses of solar cells.
25.Out of two elements A and B with mass number 2 and 235 respectively, which one is suitable for making ,
(a) a nuclear reactor, (b) a hydrogen bomb?
Name the nuclear reaction involved in each case. Write one difference between the two types of nuclear reactions.