Which of the following is impossible? Select the best answer. To cool a kitchen
ID: 1397682 • Letter: W
Question
Which of the following is impossible?
Select the best answer.
To cool a kitchen by leaving the refrigerator door open.
To build a hydro-electric plant operating at 90% efficiency.
To heat a kitchen by leaving the oven door open.
To build a gasoline engine operating at 20% efficiency
Q2-
Which of the following statements is true?
Select the best answer.
The 2nd law of Thermodynamics is a direct consequence of the 1st law.
It is impossible to transfer heat from a cooler body to a hotter body.
It is possible to convert completely work into heat
Explanation / Answer
Answer to Q1:To cool a kitchen by leaving the refrigerator door open is impossible.
Because: The refrigerators work by taking the heat out from the reservior (The inside of refrigerator) and leaving the heat to the surroundings(kitchen). So, if you keep the door open will cause more heating of kitchen instead of cooling because any heat that the refrigerator will take put from the kitchen will be given back to kitchen in addition to the mechanical energy of the refrigerator.
Leaving the oven door open will heat the kitchen as the second law of thermodynammics will be followed by flowing out of the oven(very hot) to the kitchen(comparetively cooler).
Q2)It is possible to convert completely work into heat is TRUE.
Because:
Work can be competely converted into heat but heat can not be completely connected to work. For example, if we pull a block on a rough surface for some distance and then stop. The PE of the block is same as above but the KE becomes zero as we stop and the block's temperature raises, because the work done on moving the block has been converted to the HEAT.
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