We've seen that for thermal radiation, the energy is of the form avt4, where a is a universal constant, v is volume, and t is temperature. a. the heat capacity cv also is proportional to a power of t, t^x. what is x? b. the entropy s is also proportional to a power of t, t^y. what is y? c. if a thermal radiation gas has energy 17 j, what is its helmholtz free energy f? d. if a thermal radiation gas has energy 17 j, what is its gibbs free energy?