Tag: applications of convection

Questions Related to applications of convection

It is hotter at some distance over the flames than in front of it because :

physics transfer of heat applications of convection convection thermal energy transfers

  1. air conducts heat upwards only

  2. heat is radiated upwards only

  3. convection of heat occurs upwards only

  4. heat is radiated downwards only

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Correct Option: C
Explanation:

Near flames, heat transfer occurs by both convection and radiation (and some conduction too).
But convection occurs only in upward direction. So, above the flame, it is hotter rather than in front of the flame.

Which of the following process(es) occur(s) during the convective transfer of heat within a large volume of air? 

physics transfer of heat applications of convection convection thermal energy transfers

  1. A continuous flow of warmer and cooler parts of air is established.

  2. The flow of air molecules results in flow of heat.

  3. The cooler portion of the air surrounding a warmer part exerts a buoyant force on it.

  4. As the warmer part of the air moves, it is replaced by cooler air that is subsequently warmed up.

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Correct Option: A,B,C,D
Explanation:

A continuous flow of warmer and cooler parts of air is established in which the air molecules are responsible for flow of heat. As the warmer air molecules move up, they are replaced bu cooler air molecules.