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 thermo flask thermos flask heat energy transfers transfer of heat physics

A themoflask prevent heat loss from-

  1. Conduction

  2. Convection

  3. radiation

  4. all of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
A thermoflask prevent heat loss from conduction, convection and radiation.
As it has insulator between two layers, it prevents the direct contact with surrounding and also stops the molecular motion for heat transfer. As it is a closed system surrounded by the layer of insulator, radiation can't even take place.
Multiple choice temperature control homeostasis coordination and response biology

Mechanism for cooling of human body is

  1. Sweating

  2. Crying

  3. Laughing

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • Sweating from sweat glands, often in response to heat, exercise or stress.
  • Sweating is also called as Perspiration. is the production of fluids secreted by the sweat glands in the skin of mammals. 
  • In humans, sweating is primarily a means of thermoregulation, which is achieved by the water-rich secretion of the eccrine glands. 
  •  Evaporation of sweat from the skin surface has a cooling effect due to evaporative cooling. Hence, Mechanism for cooling of the human body is Sweating. 
 So, the correct answer is 'Sweating'.
Multiple choice temperature control homeostasis coordination and response biology

Temperature of human body is maintained by

  1. Perspiration

  2. Conduction and convection

  3. Radiation

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • Core temperature is regulated by the hypothalamus (in the brain), which is often called the body’s thermostat. 
  • The hypothalamus responds to various temperature receptors located throughout the body and makes physiological adjustments to maintain constant core temperature. 
  • The human body regulates temperature by keeping a tight balance between heat gain(conduction) and heat loss(convention). And in humans, perspiration (sweating) is primarily a means of thermoregulation. Hence, Temperature of the human body is maintained by Perspiration, Conduction and convection and Radiation. So, the correct answer is 'All of the above'.
Multiple choice temperature control homeostasis coordination and response biology

What is the effect of shivering in raising the body temperature during cold weather?

  1. Shivering dilates blood vessels

  2. Shivering constricts blood vessels

  3. Shivering increases the heart rate

  4. Shivering stimulates rapid muscle action

  5. Shivering tightens skin to cause goose bumps
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Our body needs to maintain a 37°C to function properly. If it drops it could damage our organs or brain, so to stop this happening, our body strictly regulates temperature. Shivering is an involuntary pattern of repetitive, rhythmic muscle contractions. This twitching exercise produces heat, which helps to raise body temperature. Thus, the correct answer is option D.

Multiple choice temperature control homeostasis coordination and response biology

If the external temperature is low 

  1. Warm receptors are activated.

  2. Warm receptors are inhibited.

  3. Thermostat becomes operational ordering vasoconstriction of peripheral vessels and stimulation of skeletal muscles.

  4. Thermostat becomes operational ordering vasoconstriction of peripheral vessels and activation of sweat glands.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When the external temperature is low, the hypothalamus (the body's thermostat) triggers mechanisms to conserve and generate heat, such as vasoconstriction (to reduce heat loss at the skin) and shivering (to generate heat via muscle activity).

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

Heat is associated with 

  1. kinetic energy of random motion of molecules

  2. kinetic energy of orderly motion of molecules

  3. total kinetic energy of random and orderly motion of molecules

  4. kinetic energy of random motion in some cases and kinetic energy orderly motion in other.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Heating up a substance excites the molecules of that substance making  the molecules moves vigorously thus giving velocity to the molecules and we know kinetic energy of a body is by the virtue of its motion.       

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 eddy currents motional emf electromagnetic induction electromagnetic induction and alternating currents physics

Read the following statements and answer whether the given statement is true or false.

Eddy current involves loss of energy in the form of heat.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Eddy currents (also called Foucault currents) are loops of electrical current induced within conductors by a changing magnetic field in the conductor due to Faraday's law of induction. 

Eddy current involves loss of energy in the form of heat. Eddy currents flow in closed loops within conductors, in planes perpendicular to the magnetic field. They can be induced within nearby stationary conductors by a time-varying magnetic field created by an AC electromagnet or transformer. 
The statement is true.

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.