A reversible cycle may be completed in three steps, instead of the usual four. For example: (i) isothermal expansion at Th from V to V, (ii) constant-volume cooling to Tc, and (iii) adiabatic compression back to the initial state. (a) Draw a diagram for this cycle using (T, V) as the coordinates. (b) A gas obeying the equation of state pV RT + Bp is taken through this cycle. Compute AS for each step and show that AS for the whole cycle is zero. (You may assume that Cy is a constant). -