A heat engine does 9200 J of work per cycle while absorbing 22.0 kcal of heat from a hightemperature reservoir. What is the efficiency of this engine?

Answer: 9.9%

Explanation: efficiency = (work output / work input) * 100

Note that, 1 kilocalorie = 4184 joules, hence 22kcal = 22 * 4184 = 92048 joules.

Work output = 9200 j and work input = 92048 j

Efficiency = (9200/92048) * 100 = 0.099 * 100 = 9.9%