Physics · Science General

Heat Transfer Mechanisms

828 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 kirchoff's laws black body radiation heat transfer thermal properties physics

Statement-1:Good reflectors are poor emitters of thermal radiation.
Statement-2:The ratio of the emissive power (e) and absorptive power(a) is constant for all substances at any given temperture and for radiation of the same wavelength

  1. Statement-1 is true, Statement-2 is true and Statement-2 is the correct explanation for Statement- 1

  2. Statement-1 is true, Statement-2 is true but Statement-2 is not the correct explanation for Staement-1

  3. Statement-1 is true, Statement-2 is false.

  4. Statement-1 is false, Statement-2 is true.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

From the krichoff's law we know that absorptivity is equal to emissivity,so the body which emitt more wil absorbe more nor reflect more. So good reflector are poor emittor.
Now, by taking there ratio it validate krichoff's law because at any fixed or constant temperature both are equal.

Multiple choice fluid dynamics option b: engineering physics physics

A spaceship entering the earth's atmosphere is likely to catch fire. This is due to:

  1. The surface tension of air

  2. Air Friction

  3. The high temperature of upper atmosphere

  4. The greater portion of oxygen in the atmosphere at greater height.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

As the body enters Earth's atmosphere, it falls at very high speeds. This high speeds cause a lot of friction with the air, causing the parts to catch fire.
Option B.

Multiple choice fluid dynamics option b: engineering physics physics

When cooking oil is heated in a frying pan, the oil moves around in the pan more easily when it is hot. The main reason for this is that with rise in temperature, there is a decrease in

  1. density

  2. surface tension

  3. viscosity

  4. angle of contact
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

That is true. The temperature dependence of liquid viscosity is the phenomenon by which liquid viscosity tends to decrease (ore, alternatively, its fluidity tends to increase) as its temperature increase.

Multiple choice conduction in metals and non-metals thermal energy transfers physics

On a cold morning, a metal surface in touching is felt colder than a wooden surface, because the metal has:

  1. low thermal condutivity

  2. high thermal conductivity

  3. high specific heat

  4. low specific heat
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Metal appears cool on touching because heat flows from body (at higher temperature) to iron (at lower temperature). This can happen only when metal conducts heat. Wooden surface does not feel cool as it is non-conductor of heat.

Multiple choice conduction in metals and non-metals thermal energy transfers physics

On a cold morning, a metal surface will feel colder to touch than a wooden surface, because:

  1. metal has high specific heat

  2. metal has high thermal conductivity

  3. metal has low specific heat

  4. metal has low thermal conductivity
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The metal has high thermal conductivity, i.e., they conduct heat faster. and also metal is a good conductor of heat. Hence, it takes away your body heat as you touch it and which makes your body temperature to drop, therefore you feel the coldness when you touch a piece of metal.

Multiple choice conduction in metals and non-metals thermal energy transfers physics

Statement-1
On a chilly day, the metallic cap of a pen feels much colder than the plastic body although both are at the same (room) temperature.
Statement-2
Metal has a higher coefficient of thermal conductivity than plastic.

  1. Statement-1 is true, Statement-2 is true and Statement-2 is the correct explanation for Statement- 1

  2. Statement-1 is true, Statement-2 is true but Statement-2 is not the correct explanation for Staement-1

  3. Statement-1 is true, Statement-2 is false.

  4. Statement-1 is false, Statement-2 is true.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

On the chilly day the room temperature is lower than our body temperature.Since metal is better conductor than plastic when we touch the metal cap and the plastic body of a pen,heat from our finger will flow more to the metal body as compare to plastic body. Hence option (A) is correct.

Multiple choice physics heat energy transfers heat energy heat, internal energy and work internal energy

When you heat the water in a pot, it boils. What do you infer from above observation?

  1. Heat is a form of energy

  2. Water can boil itself

  3. Water develops heat on its own

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Boiling of water requires energy. Therefore heat is a form of energy since it makes the water particles to move and do work.

Multiple choice physics heat energy transfers heat energy heat, internal energy and work internal energy

Heat, as a form of energy, flows from

  1. a body of higher heat content to that of a lower heat content

  2. a body of lower heat content to that of a higher heat content

  3. a hot body to a cold body

  4. a cold body to a hot body
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Heat flows from a hot body to a cold body. Heat flow has nothing to do with the total heat content of the body.

Multiple choice physics heat energy transfers heat energy heat, internal energy and work internal energy

Heat is a from of ______

  1. Energy

  2. Work

  3. Power

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

In thermodynamics, heat is a type of energy transfer in which energy flows from a warmer substance or object to a colder one. It can be defined as the total amount of transferred energy excluding any macroscopic work that was done and any transfer of part of the object itself Transfer of energy as heat can occur through direct contact, through a barrier that is impermeable to matter (as in conduction), by radiation between separated bodies, by way of an intermediate fluid (as in convective circulation), or by a combination of these By contrast to work, heat involves the stochastic (random) motion of particles (such as atoms or molecules) that is equally distributed among all degrees of freedom, while work is confined to one or more specific degrees of freedom such as those of the center of mass.