Density of black body radiation

[asub]

I came across a formula that gives radiant energy density as 4 * sigma * T^4 / c. I am trying to figure out how this formula follows from Stefan-Boltzmann law. Shouldn't it be 4*pi instead of just 4? I am also wondering why one can just stick in c.

TIA

 

[lpfr]

I look for the same formula of Stefan-Boltzmann law and I found the same one as in wikipedia:
http://en.wikipedia.org/wiki/Black_body#Stefan-Boltzmann_law
$$j=\sigma T^4\, watts/meter^2$$
I do not understand what is your formula nor what is your problem.