Heat and Energy Exe-6C Short Answer Concise Physics ICSE Class-9 Selina Publishers

Heat and Energy Exe-6C Short Answer Concise Physics ICSE Class-9 Selina Publishers. There is the solutions of Short Answer type Questions of your latest textbook which is applicable in 2024-25 academic session. Visit official Website CISCE for detail information about ICSE Board Class-9

Heat and Energy Exe-6C Short Answer Concise Physics ICSE Class-9 Selina Publishers

Board	ICSE
Class	9
Subject	Physics
Writer / Publication	Concise Selina Publishers
Chapter-6	Heat and Energy
Exe-6C	Energy Sources
Topics	Solution of Exe-6(C) Short Answer Type
Academic Session	2024-2025

Exercise- 6C Energy Sources

(Heat and Energy Short Answer Concise Physics ICSE Class-9 Selina Publishers)

page -157

Short Answer : 

Q1- Name the two groups in which various sources of energy are classified. State on what basis are they classified.

Ans- The two groups in which various sources of energy are classified are renewable or non-conventional sources of energy and non-renewable or conventional sources of energy.

Q2- What is meant by the renewable and non-­renewable sources of energy? State two differences between them, giving two examples of each.

Ans- renewable sources- The natural sources providing us energy continuously are called renewable sources of energy.

Non-renewable: The sources of energy that have accumulated in nature over a very long period of time and cannot be quickly replaced when exhausted are called non-renewable sources of energy.

Difference between renewable and non-­renewable sources

Renewable sources	Non-renewable sources
They can be utilised continuously.	They cannot be utilised once exhausted.
Examples: Sun, Wind	Example: Coal, Petroleum

Q3- Why is the use of wood as a fuel not advisable although wood is a renewable source of energy?

Ans- Wood is obtained from trees. Hence, trees need to be cut down for wood to be used as a fuel. Also, burning wood releases a lot of smoke which pollutes the atmosphere.

Q4- Name five renewable and three non-renewable sources of energy.

Ans-Renewable sources:

1. Sun
2. Wind
3. Flowing water
4. Tides
5. Nuclear fuel

Non-renewable sources:

1. Coal
2. Petroleum
3. Natural gas

Q5- What is (i) tidal, (ii) ocean and (iii) geo thermal energy? Explain in brief.

Ans- Tidal energy: The energy possessed by rising and falling water in tides is known as tidal energy. Dams are constructed across a narrow opening to the sea to harness tidal energy and produce electricity. However, it is not a major source of energy as the rise and fall of seawater during tides is not enough to generate electricity on a large scale.

Ocean energy: Water in the oceans possesses energy in two forms:

Ocean thermal energy- The energy available due to the difference in temperature of water at the surface and at deeper levels of ocean is called the ocean thermal energy. This energy is harnessed for producing electricity by a device called ocean thermal energy conversion power plant (OCTEC power plant).

Oceanic waves energy- The kinetic energy possessed by fast moving oceanic (or sea) waves is called oceanic waves energy. Though models have been made to generate electricity from oceanic waves, but so far it has not been put to practical use.

Geo thermal energy:  The heat energy possessed by the rocks inside the Earth is called geothermal energy. The hot rocks present at the hot spots deep inside the Earth, heat the underground water and turn it into steam. This steam is compressed at high pressure between the rocks.

Holes are drilled deep into the Earth up to the hot spots to extract the steam through pipes, which is utilized to rotate the turbines connected to the armature of an electric generator to produce electricity.

Q6- State two advantages and two limitations of producing electricity from solar energy.

Ans- Advantages of using solar panels:

1. They do not cause any pollution in the environment.
2. Running cost of solar panel is almost zero.
3. They last over a long period of time.
4. They do not require any maintenance.
5. They are suitable for remote and inaccessible places where electricity power lines cannot be laid.

Disadvantages of using solar panels:

1. The initial cost of a solar panel is sufficiently high.
2. The efficiency of conversion of solar energy to electricity is low.
3. A solar panel produces d.c. electricity which cannot be directly used for many household purpose.

Q7- State two advantages and two limitations of using wind energy for generating electricity.

Ans- Advantages of using wind energy:

1. It does not cause any kind of pollution.
2. It is an everlasting source.

Limitations of using wind energy:

1. The establishment of a wind farm is expensive.
2. A large area of land is needed for the establishment of a wind farm.

Q8- What is nuclear energy? Name the process used for producing electricity using the nuclear energy.

Ans- Nuclear energy  is the energy released by the atom’s nucleus during a nuclear reaction. It is an exothermic process. The process of Nuclear fission is used to produce electricity.

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