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

Answer

B

Explanation

For Carnot engine using as refrigerator
`W = Q_(2) ((T_(1))/(T_(2))-1)`
If is given `eta = (1)/(10) rArr eta =1 - (T_(2))/(T_(1))`
`rArr (T_(2))/(T_(1)) = (9)/(10)`
So `Q_(2) = 90 J (as W = 10 J)`