90J
100J
1J
99J
Efficiency of heat engine η= (QH−QL)/QH = 0.1 (Given)
Coefficient of performance of refrigerator β = QL/(QH−QL) (2)
Or β = QL/(QH × η). (3)
Given : W = QH−QL = 10 J
Putting in (2) we get β = QL/10.. (4)
From (4) and (5), we get
∴ QL/10 = QL/QH × 0.1
⇒ QH = 100 J
Thus heat absorbed at lower temperature QL = QH−W
∴QL = 100 − 10 = 90 J