Question

A carnot engine takes in heat from a reservoir of heat at 427°C and gives out heat to the sink at 77°C. How many calories of heat must it take from the reservoir in order to produce useful mechanical work at the rate of 357 watt?

Answer 1

Explanation:

efficiency = useful work / energy taken = 1 - (Tsnk/Tsou)

So useful work / energy taken = 400/527

Thereforc energy to be taken = (527/400) * useful work = (527/400) * 750 = 988,125W

1 W = (1/4.180) cal/s

Hence energy in cal to be taken right from reservoir = 988.125 * 1/4.180 = 236.4 cal

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