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 heat - measurement introduction to temperature application of various thermometric scales different types of thermometers

Heat causes-

  1. change in temperature

  2. chemical change

  3. biological change

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

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.

Heat causes change in temperature,chemical change,biological change.

Multiple choice physics heat - measurement introduction to temperature application of various thermometric scales different types of thermometers

Heat of conduction flows in the direction of decreasing: 

  1. Temperature

  2. Pressure

  3. Density

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Heat of conduction flows in the direction of decreasing Temperature
The objects will exchange thermal energy, until thermal equilibrium is reached, i.e. until their temperatures are equal.  We say that heat flows from the hotter to the cooler object.  Heat is energy on the move.  
Units of heat are units of energy.  The SI unit of energy is Joule.  Other often encountered units of energy are 1 Cal = 1 kcal = 4186 J, 1 cal = 4.186 J, 1 Btu = 1054 J.
Multiple choice physics heat - measurement introduction to temperature application of various thermometric scales different types of thermometers

Heat flow can occur due to which of the following situation

  1. Pressure difference

  2. Temperature difference

  3. Density difference

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

Heat can be transferred from one place to another by three methods: conduction in solids, convection of fluids (liquids or gases), and radiation through anything that will allow radiation to pass. The method used to transfer heat is usually the one that is the most efficient. If there is a temperature difference in a system, heat will always move from higher to lower temperatures.

So, Heat flow occurs due to Temperature Difference

Multiple choice physics heat - measurement introduction to temperature application of various thermometric scales different types of thermometers

A physicist says "a body contains $10\ joule$ heat" but a physics learner says "this statement is correct only when the body is in liquid state". Mark correct option or options :

  1. physicist statement is correct

  2. physics learner's statement is correct

  3. both statements are correct

  4. both statements are wrong
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Heat is a form of energy in transit between systems due to a temperature difference; it is not a state function or a property contained within a body. Therefore, saying a body 'contains' heat is physically incorrect regardless of its state.

Multiple choice geography temperature process of heat transfer in the atmosphere temperature and insolation sun: the ultimate source

When both incoming and outgoing radiation are balanced, it is called _________. 

  1. heat summation

  2. heat balance

  3. heat budget

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

Sun is the main source of energy for earth. The earth 's surface receives solar energy in form of short-wave solar radiation where it is converted into heat by the process of absorption. The earth sends the same amount of energy back to space in the form of long-wave terrestrial radiation. This balance between the amount of insolation received from the sun and the outgoing terrestrial radiation is known as the earth's heat budget.

Multiple choice geography temperature process of heat transfer in the atmosphere temperature and insolation sun: the ultimate source

The atmosphere warms up by the process of _______.

  1. radiation

  2. conduction

  3. convection

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

The atmosphere warms up by the following processes:

1.  Radiation: It is the direct heating by the transmission of heat waves. The upper layer of atmosphere absorbs some amount of heat from the rays of the sun as they pass through the atmosphere.
2. Conduction: It is a process of transfer of heat by molecular activity. When two bodies with unequal temperature come into contact, there is a flow of energy from the warmer body to the cooler one. The lower layer of the atmosphere heated through the process of conduction.
3. Conversation: Transfer of heat of atmosphere from one place to another is known as conversation. Conversation is the main process in the heating of the atmosphere.

Multiple choice geography temperature process of heat transfer in the atmosphere temperature and insolation sun: the ultimate source

Which of the following term is used for transfer of heat through winds?

  1. Conduction

  2. Convection

  3. Advection

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

The term advection is used for horizontal transport of heat. Advection is responsible for slow heat transfer from the equatorial regions to the polar region. This process of heat transfer is relatively more important than any other method. The scorching winds blowing during the summer in the northern plains of India, which are known as Loo, are a typical example of advection.

Multiple choice geography temperature process of heat transfer in the atmosphere temperature and insolation sun: the ultimate source

The transfer of heat in the atmosphere by air currents is called ____________.

  1. conduction

  2. convection

  3. advection

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

Since the atmosphere is a gaseous medium, convection is the most significant mechanism of heat transfer. Heat gained by the layers of air at or near the earth's surface from radiation or conduction is usually transferred to the upper atmospheric layers by the process of convection. Thus convection is the transfer of heat in the atmosphere by the air current.

Multiple choice physics electromagnetic forces oersted experiment oersted's experiment magnetic field due to a straight current carrying conductor

Thermistor material is pressed ________

  1. under zero pressure

  2. under low pressure

  3. under high pressure

  4. under low volume
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A thermistor material is usually pressed under high pressure to form a flat cylindrical shape. Disks and washers are placed in series or in parallel to increase the power dissipation.

Multiple choice chemistry states of matter: boiling, evaporation and condensation atmospheric pressure and boiling point evaporation - factors and effects in daily life changes in physical state - boiling, evaporation and condensation

Drinking of hot tea from a saucer preferred to a cup, because:

  1. Surface area

  2. Material of the saucer

  3. Thermal conductivity

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

The surface area of milk poured in a saucer is more than that in the cup. The more the surface area, the more is the rate of evaporation which causes cooling. Therefore, the tea present in saucer becomes cool faster than in a cup.


Hence, option A is correct.

Multiple choice chemistry states of matter: boiling, evaporation and condensation atmospheric pressure and boiling point evaporation - factors and effects in daily life changes in physical state - boiling, evaporation and condensation

How does the perspiration leave cooling effect on our body?

  1. Sweat particles absorb energy from the surrounding to change into vapour thereby reducing the temperature

  2. The particles release energy into the atmosphere and the temperature decreases

  3. The particles absorb energy from the body and converts into vapour thereby increasing the temperature

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

When the ambient temperature is above body temperature, then radiation, conduction, and convection all transfer heat into the body rather than out. Since there must be a net outward heat transfer, the only mechanisms left under those conditions are the evaporation of perspiration from the skin and the evaporative cooling from exhaled moisture.