What are the success and failure?

Question

what are the SUCCESS and FAILURE of classical mechanics in terms of BLACK BODY RADIATION?

Answer 1

I can not answer for all successes and all failures.

However, if you don't use something like quantum mechanics your into concepts like the Ultraviolet catastrophe.  If there was no packets and levels of energy then energy should not have a preference about which wavelength it has.  There should be packets and pulses of energy of all different sizes.  When you get up the higher end of the frequency spectrum, this means that you could have a wave of arbitrarily short wave length.  If the wavelength could be arbitrarily short, the energy in the wave could be arbitrarily large.  Even infinite.

Quantum mechanics is more in accord with what we observe.  We are not suddenly and unexpectedly flooded with gamma rays when we turn on an oven.  Rather the energy comes out more discretely.  In measurable packets and wavelengths.