Blackbody Radiation: Planck’s idea
Eavg = ?Ei /?1 = ?P(E)*E / ?P(E)
where P(E) is the probability of having energy, E.
From probability theory we have the Boltzmann probability distribution function: P(E) = Ae-E/kT
(this is demonstrated in the next few slides).
If we assume that energy is continuous, then the summation can become an integral, and we can get a value for the average energy (which we do after discussing the Boltzmann probability distribution).