A heat engine ________.
A) converts work into heat energy
B) needs a temperature difference to be able to work
C) can be 100% efficient in the absence of friction
D) needs electricity to be able to run

Question

Quizplus · Accepted Answer

A heat engine is a device that converts thermal energy into mechanical energy or work. It does this by taking heat from a high-temperature reservoir, converting some of that heat into work, and expelling the remaining heat to a low-temperature reservoir. Therefore, it needs a temperature difference to be able to work. Option A is incorrect because a heat engine converts heat energy into work, not the other way around. Option C is incorrect because the efficiency of a heat engine can never be 100% due to the second law of thermodynamics. Option D is incorrect because a heat engine does not need electricity to run.

A Heat Engine ________