Question

For an optical resonator, what is the physical significance of the equation, n(ν)dν = 8π(ν³/c³) dν?

Answer 1

Answer

The given equation

$n(ν)dν = 8π(ν3/c3) d\nu$

The physical meaning of above is that

This shows average number of photons between frequency range $\nu$

And $\nu +d\nu$ .

This equation also tells Number of states per unit volume.