In one cycle a heat engine absorbs 530 J from a high-temperature reservoir and expels 310 J to a low-temperature reservoir. If the efficiency of this engine is 55% of the efficiency of a Carnot engine, what is the ratio of the low temperature to the high temperature in the Carnot engine?

Answer 1

The work out of the heat engine is 530-310 = 220 J per cycle and its efficiency is 220/530 = 41.5%

If the Carnot engine is 1/0.55 times higher than 41.5%, that would be 75.5%

The Tlow/Thi ratio of a Carnot engine with 74.5% effiency would have to be

1 - Tlow/Thi = 0.745
Tlow/Thi = 0.255