An ideal heat engine is operating between high and low temperature reservoirs. Suppose that now the low temperature reservoir has its temperature lowered, but no other changes are made. This temperature change affects the engine efficiency in the following way:

Question

Quizplus · Accepted Answer

The efficiency of a heat engine is given by 1 - Ql/Qh, where Ql and Qh are the amount of heat transferred from the low and high temperature reservoirs, respectively. As the temperature difference between the two reservoirs decreases, the amount of heat transferred from the high temperature reservoir decreases, but the amount of heat transferred from the low temperature reservoir remains the same. This means that the value of Ql/Qh decreases, and therefore the efficiency of the engine increases.

An Ideal Heat Engine Is Operating Between High and Low