A Carnot engine, having an efficiency of η=1/10 as heat engine, is used as a refrigerator. If the work done on the system is 10J, the amount of energy absorbed from the reservoir at lower temperature is

The efficiency (η) of Carnot engine and the coefficient of performance(β) of a refrigerator are related as β=1−ηη Here, η=110 ∴β=1−110(110)=9. Also, Coefficient of performance(β) is given by β=Q2W, whereQ2 is the energy absorbed from the reservoir.Or, 9=Q210 ∴Q2=90J.