Solution
= Solution
At $kT_d=m_Xc^2/\alpha$, division by $n_\gamma=16\pi\zeta(3)(kT/hc)^3$ gives $r(\alpha)=\sqrt{2\pi}\,\alpha^{3/2}e^{-\alpha}/[8\zeta(3)]$.
= Solution
At $kT_d=m_Xc^2/\alpha$, division by $n_\gamma=16\pi\zeta(3)(kT/hc)^3$ gives $r(\alpha)=\sqrt{2\pi}\,\alpha^{3/2}e^{-\alpha}/[8\zeta(3)]$.