Carnot's theorem

Carnot's theorem [kär′noz ′thir·əm]

(thermodynamics)

The theorem that all Carnot engines operating between two given temperatures have the same efficiency, and no cyclic heat engine operating between two given temperatures is more efficient than a Carnot engine.

The theorem that any system has two properties, the thermodynamic temperatureTand the entropyS,such that the amount of heat exchanged in an infinitesimal reversible process is given bydQ=TdS;the thermodynamic temperature is a strictly increasing function of the empirical temperature measured on an arbitrary scale.