A Carnot engine, having an efficiency of `eta=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

Options

A. `100J`
B. `99J`
C. `90J`
D. `1J`

Answer

C

Explanation

Here, `eta= 1/10, W= 10J, Q_(2)=?`
Cofficient of performance of refrigerator
`COP= (1-eta)/(et)= (Q_(2))/W`
`(1-1/10)/(1/10)=(Q_(2))/(10) :. Q_(2)= 90J`