Walker, Halliday & Resnick — Entropy and the Second Law of Thermodynamics: Problem 30

30 A Carnot engine is set up to produce a certain work \(W\) per cycle. In each cycle, energy in the form of heat \(Q_H\) is transferred to the working substance of the engine from the higher-temperature thermal reservoir, which is at an adjustable temperature \(T_H\). The lower-temperature thermal reservoir is maintained at temperature \(T_L = 250\text{ K}\). Figure 20-26 gives \(Q_H\) for a range of \(T_H\). The scale of the vertical axis is set by \(Q_{Hs} = 12.0\text{ kJ}\). If \(T_H\) is set at \(550\text{ K}\), what is \(Q_H\)?