The temperature of a heat engine is 500 k. some of the heat generated by the engine flows to the surroundings, which are at a temperature of 125 k. the efficiency of the engine is

Refer to the diagram shown below.

Q₁ = heat input
Q₂ = heat output
W = useful work

In an isentropic (reversible) process, the efficiency of the heat engine is


This is too high to be achieved in practice because an isentropic process does not occur naturally.

75%