Heat Transfer HC Verma Solutions of Que for Short Ans Ch-28 Vol-2

Heat Transfer HC Verma Solutions of Que for Short Ans Ch-28 Vol-2 Concept of Physics. Step by Step Solution of Questions for short answer of Ch-28 Heat Transfer HC Verma Question of Bharti Bhawan Publishers . Visit official Website CISCE for detail information about ISC Board Class-12 Physics.

Heat Transfer HC Verma Solutions of Que for Short Ans Ch-28 Vol-2

Board ISC and other board
Publications Bharti Bhawan Publishers
Ch-28 Heat Transfer
Class 12
Vol  2nd
writer H C Verma
Book Name Concept of Physics
Topics Solutions of Question for Short Answer
Page-Number 96, 97

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Ques for Short Ans

Objective-I

Objective-II

Exercise


Heat Transfer HC Verma Que for Short Ans

HC Verma Solutions of Ch-28 Vol-2 Concept of Physics for Class-12

(Page – 96)

Question 1 :-

The heat current is written as ΔQ/Δt. Why don’t we write

Answer 1 :-

The amount of heat crossing through any cross-section of a slab in time Δt is called heat current.
It is written as ΔQ/Δt and not ΔQ/Δt as complete derivative . This is because the amount of heat crossing through any cross section is a function of many variables like temperature difference, area of cross-section, etc. So, we cannot write it as a complete derivative with respect to time.

Question 2 :-

Does a body at 20°C radiate in a room, where the room temperature is 30°C? If yes, why does its temperature not fall further?

Answer 2 :-

Yes, the body will radiate. However, its temperature will not fall down with time because as the temperature of the surroundings is greater than the temperature of the body so, its rate of absorption will be greater than its rate of emission.

Question 4 :-

On a hot summer day we want to cool our room by opening the refrigerator door and closing all the windows and doors. Will the process work?

Answer 4 :-

No. When the door of the refrigerator is left open in a closed room, the heat given out by the refrigerator to the room will be more than that taken from the room. Therefore, instead of decreasing, the temperature of the room will increase at a slower rate.

Question 7 :-

An ordinary electric fan does not cool the air, still it gives comfort in summer. Explain

Answer 7 :-

An ordinary electric fan does not cool the air, still it gives comfort in summer because it circulates the air present in the room. Due to this, evaporation takes place and we feel cooler.

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