# Two Stefan Boltzmann Laws

1. Apr 24, 2012

### PatF

In Reif's book Fundamentals of Statistical and Thermal Physics, he labels two formulas as the Stefan-Boltzmann Law. They are both involve T^4 but the constant is different. In one, on page 376, the law is given as (pi2/15)*(kT)4/(c*hbar)3.

The other, on page 388, is (pi2/60)*(kT)4/(c2*hbar3).

The second formula is c/4 times the first.

I have looked carefully through the text and I can't see why there should be a difference. What have I overlooked?

2. Apr 25, 2012

### phyzguy

3. Apr 25, 2012

### PatF

Thanks much! I just checked and I think you are right.