Concept of Thermal Energy, Explanation and Important Questions (2024)

What is Thermal Energy?

Thermal energy is the flow of heat. The energy contained within a system that is responsible for its temperature is known as thermal energy. Thermodynamics is a branch of physics that deals with the heat transfer phenomenon between different systems and how the work is done in the process. So, it can be concluded that the energy that comes from the temperature of matter is known as thermal energy. The hotter the substance, the higher the thermal energy because the more is the vibration of molecules in it. To transfer and store heat energy, a technology is used, which is known as thermal storage, which allows the storage and transfer of heat energy or energy from ice or water or cold air.

The applications of thermal energy storage are useful in the following fields:

• Thermal storage is very useful in focussing the solar power from the solar plants to supply continuous power even during the night.
• To operate more and rapidly load changes, thermal storage is used in thermal power plants.
• Thermal storage provides heat supply security in power plants.
• Thermal storage is also useful to recover and utilise heat in processes in the industries, which prevents the loss of heat.

Important Questions on Thermal Energy

1) Which among the following energy is generated due to the motion of particles?

a) Thermal

b) Nuclear

c) Kinetic

d) Potential

Correct Option: (a)

Explanation: Thermal energy and temperature are proportional to each other because it is the result of the motion of atoms and molecules of a body. Thermal energy is the average of kinetic energy and is also responsible for the motion of a body.

2) The entire pan heats up when water is kept in a very hot pan. Which mode of heat transfer is responsible for this activity?

a) Radiation

b) Convection

c) Conduction

d) None of these

Correct Option: b

Explanation: The heat energy transfer energy due to the vibration of molecules at their positions is known as conduction; on the other hand, when the motion of molecules themselves involves the transfer of heat energy, then it is known as convection, and the heat transfer by electromagnetic waves is known as radiation. The molecules of water in immediate contact with the pan get heated when water is placed in a very hot pan, and eventually, they move away, allowing the colder molecules to settle down and get heated. This movement of heated molecules is known as convection.

3) Which one of the following is correct?

a) Radiation does not require any medium

b) Heat transfer by the vibration of particles at their position is known as convection

c) Heat transfer by the movement of particles is known as conduction.

d) The heat of the gas flame heating the cooking pan is because of the radiation process.

Correct Option: (a)

Explanation: Statement one is correct because radiation does not require any medium for the transfer of heat. Conduction is the process responsible for heat transfer from the flame to the pan when a cooking pan is heated over a gas stove. Radiation includes electromagnetic waves for heat transfer which is also known as radiant energy.

4) Thermal energy is an example of _____.

a) Kinetic energy

b) Nuclear energy

c) Potential energy

d) Mechanical energy

Correct Option: (a)

Explanation: The average measure of kinetic energy is known as thermal energy. Thermal energy is produced because of the motion of the atoms and molecules of a body. Thermal energy, which is an example of kinetic energy, is responsible for the motion of a body.

5) The faster the body moves, the higher the thermal energy. Is it true or false?

a) True

b) False

Correct Option: (a)

Explanation: The faster the object moves, the higher the thermal energy because thermal energy is a type of kinetic energy. So, the above statement regarding thermal energy is true, and the measure of an average of kinetic energy is thermal energy.

6) _____ of particles results in the rise of thermal energy.

a) Atoms

b) Vibration

c) Shape

d) Molecules

Correct Option: (b)

Explanation: Due to the vibration of particles, the temperature increases, and as we know that temperature and thermal energy are directly proportional to each other, so the vibration of particles results in the rise of thermal energy.

7) _____ may not be a source of thermal energy.

a) Heater

b) Sun

c) Moon

d) Microwave

Correct Option: (c)

Explanation: Thermal energy is also known as heat energy. The moon does not produce any heat while the other three, that is, heater, Sun and microwave, produce heat.

8) Boiling kettle is an example of _____.

a) Only kinetic energy

b) Both kinetic and thermal energy

c) Only potential energy

d) Kinetic and potential energy

Correct Option: (b)

Explanation: A boiling kettle causes the liquid’s temperature to rise when it produces heat. Thermal energy is produced as the temperature rises, which is a type of kinetic energy, so the correct option is both kinetic and thermal energy.

9) Through how many ways does thermal energy transfer occur?

a) 1

b) 2

c) 3

d) 4

Correct Option: (c)

Explanation: Conduction, convection, and radiation are the 3 ways through which thermal energy can transfer. Convection is possible with fluids; conduction needs direct contact of particles and radiation through electromagnetic waves.

10) In which of the following particles is convection not possible?

a) Water

b) Milk

c) Atmosphere

d) Iron

Correct Option: (d)

Explanation: One of the ways of transferring thermal energy is convection, which is possible only in fluids which include liquids and gases. So, convection is not possible in solids like iron. The atmosphere is a gas, whereas milk and water are liquids.

Practice Questions

1) Define energy.

2) What is thermal energy?

3) What is the difference between kinetic and potential energy?

4) What is heat transfer by conduction and convection?

5) What is renewable energy?

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