I do not know where to begin on solving these questions.

The questions are as follows:

1. If the angular frequencies of waves in a three-dimensional box of sides L generalize to:

Ω = πc/L (n

*x*²+n

*y*²+n

*z*²)^1/2

Where all n are integers, show that the number of distinct states in the frequency interval

*f*to

*f*+ Δ

*f*(

*f=*Ω/2π) is given by (where

*f*is large)

dN = 4π(L^3/c^3)

*f*²d

*f*

2. Let the energy density in the frequency interval f to f + df within a blackbody at temperature T be dU(

*f*,T). Show that the power emitted through a small hole of area ΔA in the container is

c/4dU(

*f*,T)ΔA

THANK YOU!