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 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.

Multiple choice physics effects of electric current joule's law of heating thermal effect of electric current heating effect of electric current

Joule's heating effect is

  1. Reversible

  2. Irreversible

  3. Both

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

Joule heating effect is irreversible that means if the direction of current in a resistor is reversed, the cooling of resistor does not occur whereas heating of the resistor takes place.

Heat produced via Joule's heating effect    $H = i^2Rt$ 

Multiple choice physics effects of electric current joule's law of heating thermal effect of electric current heating effect of electric current

 When electric current is passed through conductor i.e. generates heat due to resistance it offers to current flow. What this phenomena known as :

  1. Burning effect of electricity

  2. Potential Effect of electricity

  3. Heating effect of electricity

  4. Floating effect of electricity
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The phenomenon of generating heat due to the resistance of the conductor when a current passes through it is known as heating effect of electricity.

Heat produced     $H = I^2Rt$

Multiple choice physics effects of electric current joule's law of heating thermal effect of electric current heating effect of electric current

Which of the following statement is correct?

  1. seebeck effect is irreversible.

  2. Thomson effect is localised at the junction.

  3. Joule heating effect is indeoendent of the direction of flow of current in a conductor.

  4. Thomson effect is similer in origin to pelteir effect. They both are due to non-uniform distribution of electrons in a metal.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Joule heating (also referred to as resistive or ohmic heating) describes the process where the energy of an electric current is converted into heat as it flows through a resistance.

In particular, when the electric current flows through a solid or liquid with finite conductivity, electric energy is converted to heat through resistive losses in the material. The heat is generated on the microscale when the conduction electrons transfer energy to the conductor's atoms by way of collisions. It does not depend upon the direction of flow of current, but its amount.

Multiple choice physics effects of electric current joule's law of heating thermal effect of electric current heating effect of electric current

Laws of heating are given by

  1. Joule

  2. Ohm

  3. Maxwell

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

Laws of heating are given by Joule 

Joule's Heating Effect:- When an electric current is passed through the conductor, it becomes hot and its temperature starts rising. This is known as the heating effect of current or Joule's heating effect.

Multiple choice physics effects of electric current joule's law of heating thermal effect of electric current heating effect of electric current

The $1847$ Joule's experiment was aimed at.

  1. Determining the mechanical equivalent of heat

  2. Determining the temperature for the maximum density of water

  3. Investigating the heating effect of electric current

  4. Investigating the internal energy of a gas
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

James Prescott Joule performed experiments in the 1840s to demonstrate that heat is a form of energy. His work established the mechanical equivalent of heat, showing that a specific amount of mechanical work could produce a specific amount of heat.

Multiple choice physics transfer of heat applications of convection convection thermal energy transfers

In which of the following process, convection does not takes place primarily?

  1. sea and land breeze

  2. Boiling of water

  3. warming of glass of bulb due to filament

  4. heating air around a furnace
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Heat transfer of glass bulb from filament is through radiation. 
A medium is required for convection process.
As a bulb is almost evacuated, heat from the filament is transmitted through radiation.
Multiple choice physics thermal energy transfers applications of convection convection transfer of heat

While measuring the thermal conductivity of liquids, the upper part is kept hot and lower one cool so that :

  1. convectional flow is stopped

  2. radiation is stopped

  3. conduction is easier

  4. it is easier to perform the experiment
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Heat flows from hotter part to colder part and the above arrangement is done to avoid convection currents.