The energy provided each hour by heat to the turbine in an electric power plant is 9.0*10^12 J. If 5.4 * 10^12 J of energy is exhausted each hour from the engine as heat, what is the efficiency of this heat engine?

60 %

Explanation:

Efficiency is defined as the ratio of output power to the input power.

Input energy each hour = 9 x 10^12 J

Output energy each hour = 5.4 x 10^12 J

Efficiency = Output energy per hour / input energy per hour

Efficiency = (5.4 x 10^12) / (9 x 10^12) = 5.4 / 9 = 0.6

Efficiency in percentage form = 0.6 x 100 = 60 %