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 modelling gases - the kinetic model ideal gases kinetic theory of gases physics

solids expand on heating because

  1. Kinetic energy of the atoms increases

  2. Total energy of the atoms increases

  3. The potential energy curve is asymmetric atoms

  4. none of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Solids expand on heating because the potential energy curve of interatomic bonds is asymmetric. As atoms vibrate with higher energy at elevated temperatures, their average interatomic distance increases, leading to thermal expansion.

Multiple choice geography in search of the source of wind global pressure belts pressure belts atmospheric conditions

Trade wind are due to __________.

  1. conduction

  2. convection

  3. radiation

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

Trade winds are result of combination of both convection of air currents and rotation of earth.

Due to warmer air at equator the process of convection takes place where heat is transferred to the lower heat areas from higher heat areas.

Thus warmer winds are moved towards the each pole respectively from equator and due to rotation of earth these winds fall back to the equator.

These winds blow nearly constantly and always in the same direction. The trade winds have been used for many centuries to decrease the transit time of ships traveling around the world.

Multiple choice particles of a gas ideal gases physics

Smoke rising from chimneys is example of

  1. Thermionic radiation

  2. Heating of molecules in a substance

  3. Motion of molecules in a substance

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

Due to diffusion, smoke molecules leave the chimney and spreads in the atmosphere.Overall a diffusion process is seen in it as smoke particles diffuse into air particles.

Multiple choice particles of a gas ideal gases physics

In convection,

  1. Heat transfers by radiation of infrared waves

  2. Heat transfers by motion of molecules in a substance

  3. Heat transfers by collision of molecules

  4. All of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In convection, heat transfer occurs because of motion of molecules of substance in upward direction.Convection, occurs due to temperature differences which affect the density, and thus relative buoyancy, of the fluid. Heavier (more dense) components will fall, while lighter (less dense) components rise, leading to bulk fluid movement.

Multiple choice laws of heat transfer heat and thermodynamics physics

Water is used to cool radiators of engines, because:

  1. Of its lower density

  2. It is easily available

  3. It is cheap

  4. It has high specific heat
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Water has a very high specific heat capacity, meaning it can absorb a large amount of heat energy for a relatively small increase in temperature, making it an excellent coolant.

Multiple choice chemistry chemical kinetics introduction to chemical kinetics understanding chemical kinetics rate of chemical reaction

If the door of a refrigerator is kept open in a dosed room then room:

  1. heated

  2. cooled

  3. heated or cooled depending upon the initial temperature of the room

  4. neither cooled nor heated
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When the action of fridge is running, it takes air inside the fridge and cools it by removing heat from it and this heat come out from the back of fridge by a little fan. More heat comes outside the fridge. So if you even open the fridge door the cool air escape the fridge will heats up the room more ten cooling.  

Multiple choice biology human influences on the environment human intervention in ecosystems humans in the environment involvement of humans in the conservation of environment

An increase in albedo would be accompanied by ___________ in radiative equilibrium temperature.

  1. An increase

  2. A decrease

  3. No change

  4. Unstable oscillations
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Albedo is the measure of reflectivity of a surface. An increase in albedo means more solar radiation is reflected back into space, which results in less energy being absorbed by the Earth, leading to a decrease in the radiative equilibrium temperature.

Multiple choice evs atmosphere- wind importance of oxygen is air present everywhere around us? air as a natural resource

Which of the following statement is true?

  1. Hot air expands on heating.

  2. Hot air contracts on cooling.

  3. Cold air contracts on heating.

  4. None of the above.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Air is a mixture which is composed of several gases like oxygen 21%, nitrogen 78%, carbon dioxide 0.03% and water vapors. The air molecules are held by strong intermolecular forces. When air is heated up, the air molecules absorb the heat and the intermolecular forces between the air molecules become weak and its kinetic energy increases. The air molecules move apart and become less dense and thus they expand on heating.
So, the correct answer is option A.
Multiple choice chemistry changes around us can all changes be reversed? substances and objects classification of changes

Which of the following represents a reversible change?

  1. A metal rod on heating expands (its length increases).

  2. A metal rod on cooling contracts (its length decreases).

  3. Both of the above

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

The following represents a reversible change. A metal rod on heating expands (its length increases). A metal rod on cooling contracts (its length decreases).

Multiple choice chemistry changes around us can all changes be reversed? substances and objects classification of changes

Heating will produce what sort of change?

  1. An irreversible change

  2. A reversible change

  3. Either a reversible or irreversible change

  4. Neither a reversible or irreversible change
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Either reversible or irreversible change.

Reversible $-$ if there is a change of state for eg. melting, boiling 
           ${ H } _{ 2 }{ O } _{ \left( l \right)  }\rightleftharpoons { H } _{ 2 }{ O } _{ \left( g \right)  }$
Irreversible $-$ if the structural arrangement of the atom is changed.
eg : Burning of wood, kerosene etc.

Multiple choice biology physical resources air as a natural resource types of chemical reactions chemical reactions

Which process takes place inside the living system only?

  1. Burning

  2. Respiration

  3. Heating

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

Respiration is a process that utilizes oxygen to breakdown glucose and release energy in the form of heat and ATP. It is a slow process that occurs inside living system only. However, burning is a fast process that occurs outside a living system.

Multiple choice chemistry air and water pollution ways to prevent air pollution ways to reduce air pollution reducing air pollution

If heat radiated from Earth's surface is retained, outcome will be:

  1. formation of smog

  2. green house effect

  3. van der Waals forces of attraction among smoke particles

  4. all of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The greenhouse effect is the process by which radiation from a planet's atmosphere warms the planet's surface to a temperature above what it would be without its atmosphere. The exchange of incoming and outgoing radiation that warms the Earth is often referred to as the greenhouse effect because a greenhouse works in much the same way. Incoming UV radiation easily passes through the glass walls of a greenhouse and is absorbed by the plants and hard surfaces inside. Weaker IR radiation, however, has difficulty passing through the glass walls and is trapped inside, thus warming the greenhouse. This effect lets tropical plants thrive inside a greenhouse, even during a cold winter.

Multiple choice chemistry combustion extinguishing fire ways to control fire combustion, fuels and flame

Why electrical equipment on burning do not extinguished fire by water? 

  1. Water shows exothermic reaction with electrical equipment.

  2. Water conduct electricity with electrical equipment's.

  3. Water shows endothermic reaction.

  4. Water is a combustible substance.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Water conducts electricity with electrical equipment's. Hence the area under water is developed with electricity. Therefore water is not used to the extinguished fire caused by electrical equipment.


Hence, the correct option is $B$

Multiple choice chemistry combustion extinguishing fire ways to control fire combustion, fuels and flame

When paper is wrapped around an aluminium pipe ____________.

  1. ignition temperature reduces

  2. ignition temperature increase

  3. no change in ignition temperature

  4. the paper and aluminium catches fire very easily
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The ignition temperature of paper is lower compared to that of aluminium. When paper is wrapped around an aluminium pipe; the ignition temperature increases. That is why paper itself catches fire easily whereas a piece of paper wrapped around an aluminium pipe does not.

Multiple choice physics heat engine: second law of thermodynamics conversion of heat into work: heat engine and it's efficiency engines and cycles heat engines refrigerators and heat pumps

The efficiency of a heat engine : 

  1. is independent of the temperature of the source and the sink

  2. is independent of the working substance

  3. can be 100%

  4. is not affected by the thermal capacity of the source or the sink
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Efficiency is defined as work done per unit of heat consumed . It doesn't depend on the substance on which we work.