Consider a carnot engine that uses as the working substance a photon gas. (a) Given h and

Question:

Consider a carnot engine that uses as the working substance a photon gas.
(a) Given τh and τl as well as V1 and V2, determine V3 and V4.
(b) What is the heat Qh taken up and the work done by the gas during the first isothermal expansion? Are they equal to each other, as for the ideal gas?
(c) Do the two isentropic stages cancel each other, as for the ideal gas?
(d) Calculate the total work done by the gas during one cycle. Compare it with the heat taken up at τh and show that the energy conversion efficiency is the Carnot efficiency.