JEE Main 2022 Physics question
A heat engine operates with the cold reservoir at temperature 324 K. The minimum temperature of the hot reservoir, if the heat engine takes 300 J heat from the hot reservoir and delivers 180 J heat to the cold reservoir per cycle, is K.
Answer: 540
Solution
The efficiency is − 180)/300 = 2/5, and for a reversible engine − 324/. So 324/ = 3/5 and = 540 K.