Please refer to Sources of Energy Class 10 Science Important Questions with answers below. These solved questions for Chapter 14 Sources of Energy in NCERT Book for Class 10 Science have been prepared based on the latest syllabus and examination guidelines issued by CBSE, NCERT, and KVS. Students should learn these solved problems properly as these will help them to get better marks in your class tests and examinations. You will also be able to understand how to write answers properly. Revise these questions and answers regularly. We have provided Notes for Class 10 Science for all chapters in your textbooks.

Important Questions Class 10 Science Chapter 14 Sources of Energy

All Sources of Energy Class 10 Science Important Questions provided below have been prepared by expert teachers of Standard 10 Science. Please learn them and let us know if you have any questions.

Very Short Answer: 

Question: Name the largest component of bio-gas.
Answer: Methane

Question: Name the ultimate source of energy of fossil fuels.
Answer: Sun

Question: Name two dams/projects which faced opposition over their construction
from the local public.
Answer: Tehri Dam at river Ganga Sardar Sarovar Dam at river Narmada

Question: Which power plant works on the earth gravity?
Answer: Hydropower plant

Question: List two practical uses of bio-gas in rural areas.
Answer: 1. Used for lighting
2. The slurry left behind is removed periodically and used as an excellent manure, rich in nitrogen and phosphorus

Question: Name the energy resource which can be utilized in the treatment of cancer.
Answer: Radiation therapy

Question: Which isotope of uranium can undergo fission readily?
Answer: Uranium 238 or U-238

Question: Name the energy obtained from sea or ocean water due to the difference in temperature at the surface and in deeper sections of these water bodies.
Answer: Ocean thermal energy

Question: The increase in demand for energy is affecting our environment adversely. List two such effects.
Answer: 1. Burning fossil fuels cause air pollution
2. Assembly of a device with solar cells causes environmental damage.

Short Answer:

Question: How does burning of fossil fuels cause air and soil pollution?
Answer: Burning fossil fuels (coal and petroleum) cause air pollution.
The oxides of carbon, nitrogen and sulphur that are released on burning fossil fuels, they are acidic oxides. This lead to acid rain which affects air and water resources.
Increased emissions of Carbon dioxide gas contribute to greenhouse effect.

Question: Which part of the solar energy is responsible for heating the surfaces?
Answer: Only a small part of solar energy reaches the outer layer of Earth’s atmosphere (in the form of electromagnetic radiations). Half of it is absorbed while passing through the atmosphere (mostly harmful UV radiations). Rest electromagnetic
radiations reach the earth and are responsible for heating

Question: State the energy conversion taking place in the solar cell panel. For what purpose, solar cell panel is used? State its two main advantages.
Answer: The energy conversion taking place in a solar panel, solar energy→ electricity Solar cells combined in an arrangement is called a solar panel. The purpose of the solar panel is to harness solar energy and deliver enough electricity for practical use.
The two main advantages of solar panel are-
•No moving parts, require less maintenance and work satisfactorily without a focusing device.
•They can be set up in remote or inaccessible Hamlets, or very sparsely inhabited areas, in which laying of power transmission line may be expensive or not commercially viable.

Question: What are the criteria you would consider when trying to categorise something as a good fuel?
Answer: A good fuel would be one which is:-
Easily accessible
Easy to store and transport
Economical
And would do a large amount of work per unit volume or mass

Question: How is the supply of electricity maintained by a wind mill when there is no wind? By a solar panel when there is no sun?
Answer: Backup facilities like storage cells take care of energy needs, during a period when there is no wind Solar cells convert solar energy into electricity. A typical solar cell can produce a voltage  of 0.5-1 V, which can produce an electricity of 1 W

Question: It is advantageous to convert bio-mass into a bio-gas rather than burning bio-mass directly. Why?
Answer: Biogas is produced from biomass (plant and animal products).
Biogas is more advantageous because Excellent fuel, which is 75% methane Burns without smoke
Leaves no residue like ash in wood, charcoal and coal burning High heating capacity Slurry left behind can be used as a manure

Long Answer:

Question: (a) How does construction of dams across the river get linked with production of greenhouse gases?
(b) How do technological inputs improve the efficiency of bio-mass fuels?
Answer: (a) The vegetation gets submerged under the waters, in a dam. It rots under anaerobic conditions and produces methane, which is a greenhouse gas.
(b) Technological inputs to improve the efficiency of bio mass fuels are:-
(i) Burning wood in a limited supply of oxygen. The water and volatile materials present in the wood get removed and charcoal is left behind.
Charcoal burns flames and is relatively smokeless and with higher heating efficiency.
(ii) Similarly, cow dung, various plant materials like residue after harvesting the crops, vegetable waste and sewage are decomposed in the absence of oxygen to give bio gas.

Question: (a) Bio-mass contains stored energy. Justify it.
(b) How does bio-gas plant help to reduce the problem of pollution?
Answer: (a) bio-mass contains stored energy as:
(i) Biomass (animal and plant products) is used to form biogas
(ii) Biomass does not have a good heating capacity, it produces a lot of smoke Cow dung, various plant materials like residue after harvesting the crops, vegetable waste and sewage are decomposed in the absence of oxygen to give biogas
Biogas is stored, and drawn through pipes for use It is an excellent fuel, gaseous state, non-polluting and high heating capacity The slurry left behind can be used as manure, rich in nitrogen and phosphorus.
(b) Biogas reduces pollution in the following ways:
It burns without smoke, leaves no residue like ash in wood, charcoal and coal burning. 
It provides a safe and efficient method of waste disposal, besides supplying energy and manure.

Question: List three energy sources that are considered to be inexhaustible. State three reasons in support of your answer.
Answer: Solar energy: a renewable source of energy, the energy produced through nuclear fusion
Wind energy: wind is also a renewable source of energy, energy can also be backed up in storage cells Energy from sea, tidal and wave energy.

Question: What is meant by wind energy farm? Write one of its practical applications.
Give any three limitations of using wind energy farm.
Answer: Number of windmills erected over a large area is known as wind energy farm.
The practical application of a windmill farm is energy output of each windmill in the farm is coupled together to get electricity at a commercial scale.
Limitations of using a wind energy farm • Wind energy farms can be established only in those areas where wind blows for a greater part of the year.
• Wind speed should be higher than 15km/hr to maintain the speed of turbine
• There should be some backup facilities like storage cells, to take care of energy needs during a period when there is no wind.

Question: (a) Name two elements which can be used for generation of electricity in a
nuclear power plant.
(b) Why could many nuclear power plants not be installed in our country?
Give two reasons.
Answer: The nucleus of a heavy atom as such uranium, plutonium and thorium can be used to generate electricity in a nuclear power plant.
Many nuclear power plants could not be installed in our country because High cost of installation High risk of environmental contamination.

Question: 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.
Answer: It is not possible to make use of solar cells to meet all our energy needs because Silicon which is used to make solar cells is abundant in nature, but availability of special grade silicon for making the solar cells is limited.
The entire process of manufacture is expensive, silver used for interconnection of solar cells in the panel adds to the cost.
Domestic use is limited due to high costs Uses of solar cells:
•Artificial satellites and space probes like Mars orbiter use solar cells as their main source of energy.
•Radio or wireless transmission systems or TV relay stations in remote locations use solar cell panels.
•Traffic signals, calculators and many toys are fitted with solar cells.

Question: State the meaning of the term “hot spot” in the context of earth crust. Write one advantage and one limitation of utilizing energy obtained from the hot spots.
Answer: Hotspot is a region, where a molten rock is trapped. It is formed in the deeper hot regions of Earth’s crust, is pushes upwards through geological changes.
When underground water comes in contact with hotspot, a stream is generated. This steam trapped in turbines is routed through a pipe to a turbine and is used to generate electricity.
Sometimes hot water from that region also finds an outlet. It is known as hot springs.
Advantage: cost of production is not much Disadvantage: there are very few such commercially viable sites, where energy can be exploited.

Question: (a) Which property of water in ocean enables it to act as a storehouse of solar energy?
(b) List three forms in which energy from ocean can be harnessed?
(c) How are they different from each other?
Answer: (a) The water at the surface of the sea is heated by the sun, while the water in the deeper sections is relatively cold. This difference in temperature (heat from the sun) is exploited at ocean thermal power plant to produce electricity.
(b) Tidal energy Wave energy Ocean thermal energy The source of tidal energy is tides, the rise and fall in the level of sea, produced by gravitational pull of moon, on the spinning earth The source of wave energy is the kinetic energy of waves The source of ocean thermal energy is the difference in temperature of water, at the surface and in the deeper sections.

Question: Slippery surface between colliding tectonic plates resulted in a huge release of energy into the sea and this resulted in massive tsunami. The 2011
devastating tsunami rolled over many parts of Japan and caused huge damages.
The disaster also caused the three reactors at Fukushima nuclear power plant to melt down which released dangerous harmful radiations into the surrounding
areas and led to national power shortage.
(a) What could be the reason for damage in nuclear reactors?
(b) How did it affect the environment and the people?
(c) Do you think nuclear energy is a future source of energy?
Answer: (a) Breakdown of the power supply and break down of the setup arrangement.
(b) Leakage of the radioactive materials and their harmful radiations
(c) The nuclear energy if utilized with proper safety and conditions can certainly help us as a good source

Question: List any three hazards of nuclear waste. How does the disposal of nuclear waste pose a problem for the plant and animal life?
Answer: The hazards of nuclear waste are:
•The major hazard is Storage and disposal of spent or used fuel – as the uranium is still decaying into harmful subatomic particles.
•Improper nuclear waste storage and disposal result in environmental contamination 
•There is a risk of accidental leakage.

Question: Aditya suggests his family to install a solar water heater at their residence.
But some of the family members were in favour of installing an electric geyser.
Ultimately the family got water heater installed.
(a) Which according to you was correct? Give two reasons in support of your answer.
(b) Mention two possible changes in the thinking of the family members because of the arguments given by Aditya.
Answer: (a) Solar water heater would have been a good choice No moving parts, little maintenance, work satisfactorily without any focusing device.
Can be set up in remote and inaccessible hamlets or sparsely inhabited areas 
(b) Possible changes in family’s thinking
(i) Harnessing the natural and greatest source of energy, the sun
(ii) Savings on electricity bills in the future

Question: List in tabular form three distinguishing features between a thermal power plant and a geothermal power plant.
Answer: