Halliday, Resnick & Walker — Entropy and the Second Law of Thermodynamics: Problem 42

42 A 270 g block is put in contact with a thermal reservoir. The block is initially at a lower temperature than the reservoir. Assume that the consequent transfer of energy as heat from the reservoir to the block is reversible. Figure 20-29 gives the change in entropy \(\Delta S\) of the block until thermal equilibrium is reached. The scale of the horizontal axis is set by \(T_a = 280\text{ K}\) and \(T_b = 380\text{ K}\). What is the specific heat of the block?