SAT Subject Physics Practice Question 418: Answer and Explanation
9. Refrigerators and freezers perform their functions by
A. converting hot air to cold air.
B. keeping hot air out with cold air pressure.
C. removing heat from inside themselves.
D. blowing cold inside them.
E. producing cold air.
Correct Answer: C
The correct answer is (C). Refrigerators and freezers operate in a reversed direction from a heat engine. Instead of using a hot source to produce work, work is done on a warm source and heat is removed, producing the cooling effect.