Available Answers

1. 1.

   Match the following.

   Column A	Column B
   i. Sun	a. Atom bomb
   ii. Charcoal	b. Semiconductors
   iii. Geothermal energy	c. Uses black paint to absorb maximum heat.
   iv. Nuclear fission	d. Nuclear fission
   v. Biogas	e. Burns without smoke
   vi. Photovaltic cell	f. Kinetic energy of wind
   vii. Solar cooker	g. Production of carbon dioxide
   viii. Windmill	h. Production of methane
   	i. Heat energy from the Earth

    

2. 2.

   State whether the statements are true or false and correct the false statements.

   1. In a solar cell, electrical energy gets converted into light energy.
   2. Still air has low kinetic energy.
   3. The availability of solar energy is highly predictable.
   4. Construction of dams for building hydroelectric power stations can cause environmental hazard.
   5. It is absolutely safe to release CFC in the atmosphere.
   6. Carbon dioxide restricts the function of the haemoglobin.
   7. Hydrogen fuel is a clean source of energy.
   8. The lid of solar cooker must be fitted with a mirror.
3. 3.

   Correlate the following.

   1. Atom bomb : Nuclear fission :: _______________ : Nuclear fusion
   2. Uranium : Nuclear energy :: Biomass : ______________
   3. Wood : Incomplete combustion :: ___________ : Complete combusion
   4. Fossil fuel : Non-renewable source :: ___________ : Renewable source
4. 4.

   What is meant by renewable sources of energy? Give two examples.

5. 5.

   State the law of conservation of energy.

6. 6.

   Name three devices that utilise solar energy for everyday purposes.