Physics · Science General

Heat Transfer Mechanisms

877 Questions

Heat Transfer Mechanisms deal with the movement of thermal energy through conduction, convection, and radiation. It involves practical applications like ocean heat storage and atmospheric heating. These fundamental physics concepts are frequently asked in general science sections.

Thermal conductionHeat convectionThermal radiationSpecific heatStates of matter

Heat Transfer Mechanisms Questions

Multiple choice

Which of the following factors do not affect the quantity of heat required to raise the temperature of a body? (a) Mass of the body (b) Nature of the substance of the body (c) Volume of the body (d) Shape of the body

  1. Only (a) and (b)

  2. Only (b) and (c)

  3. Only (a) and (d)

  4. Only (c) and (d)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • Greater is the mass of the body, more is the temperature required to heat it.
    • Nature of the substance of the body (metal, non-metal) also affect the quantity of heat required to raise the temperature of a body.
    • Volume and shape of a body do not affect the quantity of heat require to raise the temperature of a body.
Multiple choice

Soup, in general, cools slower than hot water of the same amount and temperature.

Which of the following explanations is/are correct for this fact?

(1) Evaporation of soup is hindered by a layer of oil on its surface. (2) The heat capacity of the soup is much lower.

  1. Only (1)

  2. Only (2)

  3. Both (1) and (2)

  4. Neither (1) nor (2)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Statement (1) is correct. Oil present in soup doesn't mix with water, and floats on top of water, and usually makes a very thin layer, covering all the water and it prevents the water molecules from evaporating. Statement (2) is incorrect. ‘Heat capacity’ means the amount of heat required to reach at its boiling point. The intermolecular bonds of vegetables and oil require a lot of heat to break.

Multiple choice

Consider the following statements:

1. Mercury is the only liquid in which conduction is possible.

  1. Black bodies are good radiators and poor conductors of heat.

Which of the given statements is/are correct?

  1. Only (1)

  2. Only (2)

  3. Both (1) and (2)

  4. Neither (1) nor (2)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Statement (1) is correct. Mercury is the only liquid in which conduction is possible due to its low specific heat. Statement (2) is incorrect. Black bodies are good radiators and good conductors of heat.

Multiple choice

Consider the following statements: 1. The air in a hair dryer is heated by convection.

  1. If air were a good conductor of heat, at night time the earth would be considerably cooler.

Which of the given statements is/are correct?

  1. Only (1)

  2. Only (2)

  3. Both (1) and (2)

  4. Neither (1) nor (2)
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

(i) Statement (1) is incorrect. The air in a hair dryer is heated by radiation. The air is heated by a hot, glowing coil of wire that emits radiation. (ii) Statement (2) is correct. If air were a good conductor of heat, at night time the earth would be considerably cooler because all the heat of earth is escaped in the space through air as a medium.

Multiple choice

Directions: Consider the following statements:

  1. Your feet feel warmer on a rug or carpet than on a tiled floor because a rug is a better conductor than a tile.
  2. Heaters are placed on the floor because of convection currents.

Which of the given statements is/are correct?

  1. Only (1)

  2. Only (2)

  3. Both (1) and (2)

  4. Neither (1) nor (2)
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Statement (1) is wrong. Rug or carpet acts as an insulator. It does not conduct the heat of the floor to the feet. Statement (2) is correct. Convection is the flow of heat through a bulk, macroscopic movement of matter from a hot region to a cool region.

Multiple choice

Cooking oil is poured into an iron pan, which is heated over a flame. The heated oil begins rising to the top. What is the correct order of heat transfer during the entire process?

  1. Conduction, convection, radiation

  2. Convection, conduction, radiation

  3. Radiation, conduction, convection

  4. Conduction, radiation, convection
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The flame heats the pan by radiation, heat is transferred through the pan by conduction, and heat rises through the oil by convection.

Multiple choice

Consider the following statements:

  1. The smell of hot sizzling food reaches several metres away because hot food has higher kinetic energy of the particles.
  2. A hot body radiates heat most rapidly if its surface is white and rough.

Which of the following statements is/are incorrect?

  1. Only 1

  2. Only 2

  3. Both 1 and 2

  4. Neither 1 nor 2
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Statement 1 is correct. The temperature of hot food is more. Therefore, the particles of hot vapours coming out of hot sizzling food have higher kinetic energy, i.e. they move faster and hence, the smell of hot sizzling food reaches several metres away. Statement 2 is incorrect. A body with black and rough surface absorbs heat most rapidly (it absorbs heat energy).

Multiple choice

Which of the following statements is a condition for evaporation?

  1. Heat energy absorbed is equal to the latent heat of vaporisation.

  2. Heat energy absorbed is less than the latent heat of vaporisation.

  3. Heat energy absorbed is more than the latent heat of vaporisation.

  4. Heat energy absorbed is independent of the latent heat of vaporisation.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

During evaporation, the particles at the surface of a liquid gain energy from the surroundings or body surface and change into vapours. The heat energy equal to the latent heat of vaporisation is absorbed from the body, giving a cooling effect. 

Multiple choice

Which process allows the heat transfer with the surroundings and maintains the temperature as constant?

  1. Adiabatic

  2. Isobaric

  3. Isochoric

  4. Isentropic

  5. Isothermal
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

An isothermal process is a change of a system, in which the temperature remains constant: ΔT = 0. This typically occurs when a system is in contact with an outside thermal reservoir (heat bath), and the change occurs slowly enough to allow the system to continually adjust to the temperature of the reservoir through heat exchange.

Multiple choice

Consider the following statements:

  1. Saw dust is a bad conductor of heat.
  2. Water at 0o C feels colder than ice at 0o C.

Which of the given statements is/are correct?

  1. Only 1

  2. Only 2

  3. Both 1 and 2

  4. Neither 1 nor 2
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Statement 1 is correct. Ice is generally covered with star dust as it is a poor conductor of heat. Statement 2 is incorrect. Ice at 0o C feels colder than water at 0o C due to latent heat of fusion (quantity of heat required to change liquid substance to solid).

Multiple choice

Consider the following statements:

  1. In refrigerator, the heat engine works in backward direction.
  2. The temperature of the upper part of the flame is more than the temperature on the sides.

Which of the given statements is/are correct?

  1. Only 1

  2. Only 2

  3. Both 1 and 2

  4. Neither 1 nor 2
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Statement 1 is correct. Refrigerator is an apparatus, which takes heat from a cold body, and work on it. Statement 2 is also correct. The temperature of the upper part of the flame is more than the temperature on the sides because the currents of air carry the heat upwards.

Multiple choice

Consider the following statements:

  1. Conduction of heat can take place in vacuum.
  2. In a room, ventilators are provided at the ceiling for hot air to escape by conduction.

Which of the given statements is/are correct?

  1. Only 1

  2. Only 2

  3. Both 1 and 2

  4. Neither 1 nor 2
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Statement 1 is incorrect. Conduction of heat does not take place in vacuum. Conduction only takes place in solids. Statement 2 is also incorrect. In a room, ventilators are provided at the ceiling for hot air to escape by convection. Convection takes place in liquids and gases.       

Multiple choice

Consider the following statements:

  1. Calorimeter an apparatus is used for measuring heat energy.
  2. Human body is an example of closed system.

Which of the given statements is/are correct?

  1. Only 1

  2. Only 2

  3. Both 1 and 2

  4. Neither 1 nor 2
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Statement 1 is correct. A calorimeter is an object used for calorimetry, or the process of measuring the heat of chemical reactions or physical changes as well as heat capacity. Statement 2 is incorrect. Human body is an example of open system. Open system is a system, which can exchange matter as well as energy with the surroundings is called an open system.

Multiple choice

Consider the following statements:

  1. Ice cream boxes are covered with glass wool because it allows the leakage of heat.
  2. Steam engine transforms heat into mechanical energy.

Which of the given statements is/are correct?

  1. Only 1

  2. Only 2

  3. Both 1 and 2

  4. Neither 1 nor 2
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Statement 1 is incorrect. Ice cream boxes are covered with glass wool because it is a bad conductor of heat. It does allow the transfer tof heat from surroundings to inside the box. Statement 2 is correct. Steam engine transforms heat into mechanical energy. The burning of coal produces heat, which produces the force to spin the steam turbine for the production of electricity.