DAV Class 5 Science Solution Chapter 9 Fuels
DAV School Books Class 5 Science Solution Chapter 9 Fuels all Question Answer. DAV Class 5 9th Chapter Fuels full Chapter explanation by expert teacher.
A.) Fill in the blanks.
Answer: (1) Food (2) domestic (3) kerosene (4) CNG (5) diesel (6) renewable.
B.) Write True or False for the following statements.
Answer: (1) True (2) True (3) False , powerhouses burn coal (4) False, coal is non-renewable source of enrgy (5) True.
C.) Tick the correct option.
1.) Out of the following, the fuel, that is best for reducing environmental pollution, is-
Answer: compressed natural gas
2.) A good fuel is one that-
Answer: does not produce smoke or leave ash.
3.) A fuel, that is not obtained by refining petroleum, is-
Answer: biogas
4.) Out of the following, the energy source, that is a renewable energy source, is-
Answer: wind
5.) Coal, a common fossil fuel, is formed-
Answer: by decay of vegetation, under heat and high pressure, over a long period of time.
D.) Answer the following questions in brief.
1.) State the main function of a fuel.
Answer: Fuels are burned in order to get energy (in the form of heat).
2.) Give one example each of solid, liquid and gaseous fuels.
Solid – Coal
Liquid – Petroleum
Gaseous- Compressed Natural Gas (CNG)
3.) Why is biogas regarded as a better fuel than cowdung cakes?
Biogas does not release harmful gases like carbon monoxide upon being heated up hence it is a clean fuel and better than other fuels.
4.) Why is CNG called a better green fuel?
CNG has low maintenance cost and better efficiency. It also does not cause air pollution on burning. Thus it is a better green fuel.
5.) Name the three main fossil fuels.
Answer: Petroleum, Coal and Natural gas are the main fossil fuels found on earth.
6.) State two disadvantages of fossil fuels.
- May cause pollution
- Since most of the fuels are non renewable sources of energy they might get exhausted if they are extracted way too much.
E.) Answers the following questions.
1.) How have fossil fuels been formed?
Answer: Fossil fuels were formed by the decomposition of remains of dead plants and animals that were buried under the surface of the earth and upon geological action such as extreme temperatures and pressures on top of it the remains of the animal got decomposed into fossil fuels over long period of time
2.) When is a source of energy said to be a renewable source of energy? Give two examples of such sources.
Answer: A source of energy is said to be renewable if it can be readily replenished. such sources of energy are found in abundance on earth. solar energy tidal energy wind energy are examples of such forms of energy. solar power plants are used to harness the solar energy, windmills are used to harness wind energy.
3.) When is a source of energy said to be a non-renewable source of energy? Give two examples of such sources.
Answer: Non renewable sources of energy are the ones which when exhausted ones cannot be replenished again. such sources of energy are coal and petroleum. These have been formed by the decomposition of dead remains of animals for over millions of years and for them to be renewed again it would take another million or even more years
4.) How is coal used by powerhouses for generating electricity?
Answer: powerhouses burn coal in order to evaporate water into vapour. the steam or vapor is used to turn turbines that in turns helps in generating electricity.
5.) Why should efforts need to be made to reduce the use of fossil fuels?
Answer: Since fossil fuels are not abundantly available and are non renewable sources of energy it won’t be easy to replenish them if it is not used wisely. fossil fuels also cause environmental pollution on burning hence. Their wastage and use both should be minimized. By using alternative source of energies and renewable energies the cost of fuel can be saved and also environmental pollution can be reduced