Question

In each cycle, a heat engine receives an input of 1540 J of heat and exhausts 1030 J of heat. What is the thermal efficiency?

0.274

0.456

0.669

0.331

Answer 1

The thermal efficiency of a combustion system is simply the ratio of heat out and heat in, that is:

efficiency = heat out / heat in

efficiency = 1030 J / 1540 J

efficiency = 0.669

So the efficiency is 0.669