If an engine operates on an input temperature of 800k and an exhaust temperature of 600k, calculate the efficiency of the engine.

The efficiency of a heat engine can be calculated as the ratio of the work obtained to the heat energy put in at the high temperature,

efficiency = Work_max/T high.

or

efficiency=TH-TL/TH,

where TH is the high temperature and TL is the low temperature.

In our case the heat engine operates between 600K and 800K. SO, TH=800K and TL=600K.

The efficiency is: e=800-600/800=200/800=0,25