Question

Which of the following changes would make a heat engine less efficient?

A. A decrease in its exhaust temperature
B. A decrease in entropy
C. An increase in work done
D. A decrease in its operating temperature

Answer 1

A decrease in it's operating temperature would make a heat engine less efficient. This is because in order to operate, a heat engine needs to be hot and maintain that temperature.

Answer 2

D
A decrease in operation temperature will decrease the temperature difference and reduce efficiency.