The change in internal energy during one complete cycle of a heat engine

Question

Quizplus · Accepted Answer

According to the first law of thermodynamics, the change in internal energy of a system is equal to the net heat added to the system minus the work done by the system. In a heat engine, the work done by the system is equal to the difference between the heat energy entering the engine and the heat energy exhausted from the engine. During one complete cycle of a heat engine, the system returns to its initial state and thus there is no net work done by the system. Therefore, the change in internal energy during one complete cycle is equal to zero.

The Change in Internal Energy During One Complete Cycle of a Heat