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Home Conservation Laws Thermodynamics Examples Entropy and the Carnot Engine
 
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Entropy isn’t changed by a Carnot engine

The efficiency of a heat engine is defined by

efficiency = 1 - QL/QH ,

and the efficiency of a Carnot engine is

efficiency = 1 - TL/TH ,

so for a Carnot engine we have QL/QH = TL/TH, which can be rewritten as QL/TL = QH/TH. The entropy lost by the hot reservoir is therefore the same as the entropy gained by the cold one.



Home Conservation Laws Thermodynamics Examples Entropy and the Carnot Engine

Last Update: 2009-06-21