Question

In: Physics

does a heat engine reject some heat to a lower temperature resorvoir

Expert Solution

Yes, any heat engine rejects some heat to the lower temperature reservoir.

Consider the ideal engine (Carnot engine). From a high temperature reservoir at temperature . the engine obtains amount of heat. The engine does amount of work by converting a part of this energy to work. And the engine rejects the remaining amount of energy to a lower temperature reservoir at temperature .

Efficiency of this engine

If the engine is not rejecting some heat to the lower temperature reservoir, then , that is .

Hence efficiency

But there is no Carnot heat engine with this efficiency as implies that . But absolute zero is not attainable.

Real heat engines have efficiency less than that of Carnot engine. Hence they also cannot attain the temperature of absolute zero.

Hence all engines must reject some heat to the lower temperature reservoir.

genius_generous answered 2 years ago

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