Answer Happy

Here, we consider a photon gas. Following Maxwell’s argument,
the number of photons
between momentum p and p+dp can be described as ρ(𝑝) =
(8π𝑉/ℎ3)𝑝2𝑒𝑥𝑝{− 𝑐𝑝/(𝑘𝐵𝑇)},where
𝑉 is the volume, ℎ is the Planck’s constant,and 𝑐 is
the speed of light. Derive the number of photons N as a function of
𝑇 by integrating ρ(p) over 0 to ∞.