## Essential University Physics: Volume 1 (3rd Edition)

We know that 140 Joules of work is done, for this is the change in energy. Thus, we find the efficiency: $= \frac{140}{240}=.583$ Thus, it follows: $T_h=\frac{T_c}{1-.583} = \frac{288K}{1-.583} \approx 691 K \approx 418 ^{\circ}C$