Costante di Stefan-Boltzmann: differenze tra le versioni

:<math>\sigma = \frac{(2 (\pi)^5 R^4}{15 h^3 c^2 N_{\rm A}^4} = \frac{32 \pi^5 h R^4 R_{\infty}^4}{15 A_{\rm r}({\rm e})^4 M_{\rm u}^4 c^6 \alpha^8}</math>