(a) Show that the number of photons per unit volume in a photon gas of temperature Tis app...

(a) Show that the number of photons per unit volume in a photon gas of temperature Tis approximately (2 X 107 K-3m-3)T3. (Note:

(b) Combine this with a result derived in Example 9.6 to show that the average photon energy in a cavity at temperature Tis given by