So, the cylinder are the little element, and then this equation multiplied by the volume of this element give me the energy contained in this element of the cavity. The next step are see how much of this radiation reaches the hole, then we integrate over all elements inside the cavity that reach...
So, we have the equation of the energy that are coming from definited directions by the intervals of angles θ and Φ with frequency in a determined interval, that are:
$$\left[\rho\left(\nu\right)d\nu\right]\cdot\left[\frac{\sin\left(\theta\right)d\theta d\phi}{4\pi}\right]$$
And at this moment...
Well, this is exact the fact that i am trying confirm, maybe i made some confusion betweem the entire black body and this cavity. So, i am correct when I say that i integrate θ only up to π/2 π, because I only want get radiation from inside of the cavity?
The other half are radiation coming...
Hi, my teacher showed us how we can derive de relation between spectral radiance and density of cavity (of a black hole), but I have a doubt.
This is the equation of the energy that are coming from definited directions by the intervals of angles θ and Φ with frequency in a determined interval...