Class 10 Science
Previous Years Appeared Questions and Answer
Chapter 14 Sources of Energy
Multiple Choice Questions
1. The inner surface of solar cooker is coated with black paint to (June - 2020)
(A) absorb more heat
(B) reflect light
(C) prevent rusting
(D) converge the light rays.
Ans. : (A) absorb more heat
2. The power plant in which natural source of energy is directly used to rotate turbines is (June - 2020)
(A) thermal power plant Total
(B) hydro electric power plant
(C) nuclear power plant
(D) plant solar power plant
Ans. : (B) hydro-electric power
3. Which of the following is ecofriendly ? (June 2019)
(A) Thermal power plant
(B) Hydropower plant
(C) Biogas plant
(D) Nuclear power station.
Ans: (B) Hydropower plant
One Mark Questions
1. What is a solar cell ? (Sep - 2020) (june 2023)
Ans. :
The device that converts solar energy into electrical energy.
2. Biogas plant is a boon to farmers.” Why ? (June - 2020)
Ans. :
★ The slurry left behind is used as excellent manure, rich in nitrogen and phosphorous
★ It provides a safe and efficient method of waste disposal besides supplying energy and manure.
Two Marks Questions
1. Write any two limitations of producing electricity from wind energy. (June 2023)
Ans. :
i) Wind energy farms ( wind mills ) cannot be established everywhere.
ii) The wind speed should be higher than 15 km/h to maintain the required speed of the turbine.
iii) Wind energy farms require large area of land.
iv) The initial cost of establishment of the farm is quite high. ( Any two )
2. List the characteristics of a good source of energy. (June 2019)
Ans:
★It should be a sustainable and renewable source of energy.
★ It should have a high calorific value.
★It should be easily accessible and provide energy for the maximum period of time.
★ It should not cause pollution.
Three Marks Questions
1. Which is the major component of biogas ? Write four characteristics of a good source of energy. (April - 2022)
Ans:
★ Methane / CH4
★ Characteristics of a good source of energy :
★ Which has do a large amount of work per unit volume or mass
★ Must be easily accessible / available
★ Must be easy to store and transport
Must be economical.
( Any other suitable answer )
2. Which element is used in making solar cell ? Write any four advantages of solar cells. (April - 2022)
Ans. :
★ Silicon / Si
The advantages of solar cells :
★ They have no moving parts
★ Little maintenance
★ Work quite satisfactorily without the use of any focusing device
★ Can be set up in remote areas where people cannot reach easily
★ Can set up in those areas too, where laying of power transmission line is not possible. ( Any four )
3. a) Explain how is nuclear energy generated in power reactors. How is electricity produced from nuclear energy ?
b) Mention two hazards of nuclear power reactor. (Sep - 2020)
Ans:
a)
★ Nuclear fission reaction is carried out in nuclear power reactors. The nucleus of heavy atom ( such as uranium, plutonium or thorium ) when bombarded with low-energy neutrons, can be split apart into lighter nuclei.
★ When this is done, a tremendous amount of energy is released at a controlled rate.
★ The released energy is used to produce steam and further generate electricity.
b)
Hazards of nuclear power reactor :
★ Improper / unscientific storage and disposal of spent or used fuels.
★ Accidental leakage of nuclear radiations.
★ High cost of installation of nuclear power reactor.
★ Limited availability of uranium.
★ High risk of environmental contamination. ( Any two points )
4. a) Explain why we are looking at the alternative sources of energy.
b) Mention the advantages and disadvantages associated with solar cells. (Sep - 2020)
Ans:
★ The reasons for our looking at alternative sources of energy are ;
★ the conventional sources of energy like fossil fuels are in danger of getting exhausted soon.
★ conventional sources of energy are not sufficient to run the machines to do more and more tasks.
★ unlimited use of conventional sources of energy has led to the problem of energy crisis.
★ uncontrolled use of conventional sources of energy has created many problems of environmental pollution. ( For any two reasons ).
b)
Advantages associated with solar cells :
★ They have no moving parts
★ They require little maintenance
★ They work quite satisfactorily without the use of any focussing device T
★ They can be set up in remote and inaccessible hamlets or very sparsely inhabited areas in which laying of a power transmission line may be expensive. ( Any two advantages )
Disadvantages associated with solar cells :
★ Availability of special grade silicon for making solar cells is limited.
★ The process of manufacture of solar cells is very expensive.
★ Silver used for interconnection of the cells in the panel is very costly.
★ Their efficiency is low.
( Any two advantages )
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