The equation of state for radiant energy in equilibrium with the temperature of the walls of a cavity of volume V is P = (aT^4)/3 , where a is a constant. The energy equation is U = (aT^4)V .
(a) show that the heat supplied in an isothermal doubling of the volume of the cavity is (4/3)(aT^4)V .
(b) show that in an adiabatic process, VT^3 is constant