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

Answer

B

Explanation

Here, `eta=1/10, W= 10J, Q_(2)=?`
For engine and refrigerators operating between same two temperatures, cofficient of performance,
`beta=(1-1//10)/(1//10)=9`
As `beta=(Q_(2))/W` (from the principle of refrigerator)
`:. 9 = (Q_(2))/(10) or Q_(2)= 90J`