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 physics transfer of heat applications of heat conduction applications of insulation clothes - our necessity

Air is a bad conductor of heat because:

  1. it's molecules are in continuous contact with each other.

  2. it's molecules are not in continuous contact with each other

  3. it's molecules absorb all the heat

  4. it's molecules are moving randomly due to Brownian motion
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Air is a bad conductor of heat because it's molecules are not in continuous contact with each other.
Air molecules are too far to disperse heat energy to one another efficiently. Heat is conducted by molecules and atoms that are very closely bonded together and vibrating at high frequency.
Multiple choice physics transfer of heat applications of heat conduction applications of insulation clothes - our necessity

.................. surface absorbs more heat than any other surface under identical conditions.

  1. White & Shiny

  2. White & Rough

  3. Black & Rough

  4. Yellow & Shiny
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Black & rough surface absorbs more heat than any other surface under identical conditions.
Black surface absorbs all the radiations more easily than any surface as its absorptivity is $1$.
Multiple choice physics transfer of heat applications of heat conduction applications of insulation clothes - our necessity

The heat transfer in air is poor because

  1. it take place mainly due to convection

  2. it take place mainly due to conduction

  3. it take place mainly due to radiation

  4. all of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Air is a gas and its molecules are far apart from each other. So, this is not a good condition for conduction. Also, air being a non-metal doesn't have free electrons for conduction. Hence option B is not applicable.

C is also not applicable because radiation doesn't need any medium. Air being a fluid, convection can take place through it. But convection is not a very fast mode of transfer of heat.

Multiple choice physics transfer of heat applications of heat conduction applications of insulation clothes - our necessity

How does air trapped by the woolen fabric help ?

  1. Air is a good conductor of heat and allows warm air to come near body

  2. Air is a bad conductor of heat and allows body heat to escape into atmosphere

  3. Air is a bad conductor of heat and doesn't allow body heat to escape into atmosphere

  4. Air is a good conductor of heat and doesn't allow cool air to come near body.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Air trapped by the woolen fabric help us during winter. As air is bad conductor of heat and doesn't allow body heat to escape into atmosphere. The heat stored inside the body does not goes out as wool and air acts as a layer of insulator. And body heat is not escaped from the body.

Multiple choice evs - i transfer of heat clothes - our necessity applications of insulation uses of good and poor conductors in daily life voyages and discoveries applications of heat conduction

A shining metallic ball with a small black spot on its surface is heated to very high temperature and then quickly taken to a dark room. Then.

  1. Both appear equally bright

  2. The spot appears brighter than the ball

  3. The spot appears darker than the ball

  4. Both are invisible in the dark room
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

According to Kirchhoff's law of radiation, good absorbers are good emitters. A black spot is a better absorber than the shiny surface, so it will emit more radiation and appear brighter when the object cools in a dark room.

Multiple choice physics heat and energy zeroth law of thermodynamics

Two bodies A and B are said to be in thermal equilibrium with each other, if :

  1. heat flows from A to B

  2. heat flows from B to A

  3. both the bodies lose equal amounts of heat to the atmosphere

  4. heat does not flow from either A or B
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The correct answer is option(D).

Thermal equivalence happens when there is no temperature difference between two bodies. And no heat transfer happens.

Multiple choice physics heat and energy zeroth law of thermodynamics

Two bodies are in thermal equilibrium if they have same

  1. temperature

  2. amount of heat

  3. specific heat

  4. thermal capacity
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Thermal equilibrium means that there is no heat transfer going on between the bodies, which simply means that the bodies are at the same temperature. Heat content is a whole different concept - it is the amount of heat contained in a body, which is crucially dependent on mass. 

Multiple choice physics heat and energy zeroth law of thermodynamics

Two bodies A and B are said to be in thermal equilibrium with each other, if

  1. heat flows from A to B

  2. heat flows from B to A

  3. both the bodies lose equal amunts of heat to the atmosphere

  4. heat does not flow from either A or B
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Two bodies A and B are said to be in thermal equilibrium with each other, ifheat does not flow from either A or B 

Multiple choice physics heat and energy zeroth law of thermodynamics

In thermal equilibrium concepts, heat lost by hot body is equal to

  1. Heat gained by hot body

  2. Heat gained by cold body

  3. Both (a) and (b)

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

It is very clear that heat flows from hot body to cold body under general conditions. 

So (B) is the correct option. 

Multiple choice physics heat and energy zeroth law of thermodynamics

Two bodies are said to be in the state of thermal equilibrium if there is no transfer of heat taking place between them. True or false.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Thermal equilibrium is said to be achieved when there is no exchange of heat in the system.
Hence, OPTION : A (true).
Multiple choice physics free, damped and forced oscillations damped harmonic motion damped oscillation free, forced and damped oscillations

In which of the following there is some loss of energy in the form of heat

  1. Forced vibrations

  2. Free vibration

  3. Damped vibrations

  4. All
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

It is our common experience that when a body is made to vibrate in a medium , the amplitude of the vibrating body continuously decreases with time and ultimately the body stops vibrating.this is called the damped vibrations.

Multiple choice

What is the main energy transfer taking place when a gas fire burns?

  1. Chemical to light

  2. Chemical to thermal

  3. Fuel to sound

  4. Light to thermal
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When gas burns, the chemical energy stored in the fuel bonds is released as thermal energy (heat). While light is also produced, the primary purpose and main energy transfer in a gas fire is the conversion to heat.