Chapter 19 - Heat Engines and Refrigerators - Exercises and Problems - Page 551: 29

a) $Q_H= 60J$ b)$T_C =250K =- 23^oC$

a) We have $K= 5.0$ and $W= 10J$ But $ K = Q_C/W$ $ 5 = Q_C/10J$ $Q_C = 50J$ Hence $Q_H = W+Q_C$ $Q_H = 10J + 50J $ $Q_H= 60J$ b) we have $T_H = 300K$ $ \frac{T_H}{T_C} =\frac{Q_H}{Q_C}$ $ T_C = \frac{Q_C}{Q_H} T_H$ $ T_C = \frac{50}{60} 300K$ $T_C =250K =- 23^oC$