If the efficiency of a Carnot engine were to be 100%,the heat sink would have to be
A)at absolute zero.
B)at 0°C.
C)at 100°C.
D)infinitely hot.

Question

Quizplus · Accepted Answer

According to the second law of thermodynamics, it is impossible for a heat engine to completely convert all of the heat it receives into mechanical work. This means that a perfectly efficient engine (which converts all of the input heat into work) cannot exist. The efficiency of a Carnot engine (the most efficient possible heat engine) is given by the ratio of the temperatures of the hot and cold reservoirs, so to increase the efficiency to 100%, the temperature of the cold reservoir must be reduced to absolute zero. Thus, the best choice is A) at absolute zero.

If the Efficiency of a Carnot Engine Were to Be