Q. The thermal efficiency of a reversible heat engine operating between two given thermal reservoirs is 0.4. The device is used either as a refrigerator or as a heat pump between the same reservoirs. Then the coefficient of performance as a refrigerator (COP)_R and the co-efficient of performance as a heat pump (COP)_HP are

• (A) (COP)_R = (COP)_HP = 0.6
• (B) (COP)_R = 2.5; (COP)_HP = 1.5
• (C) (COP)_R = 1.5; (COP)_HP = 2.5
• (D) (COP)_R = (COP)_HP = 2.5