physics Carnot heat engine?

Question

A Carnot heat engine operates between reservoirs at Th= 1545 K and Tc= 150 K. in each cycle, 250 joules of heat energy is rejected to the low temperature reservoir. in each cycle, how much mechanical work W is performed by the engine?

Answer 1

THe efficiency of teh engine, h is

h = (Th - Tc)/Th

The heat rejected Qr is (1-h)*work done = (1-h)Qw so

Qr = Qw(1-h) ---> Qw = Qr/(1-h)

Plug in the values provided and solve.