The book QM Demystified states this about black body radiation spectrum:
An attempt to explain these results using classical theory was codified in the Rayleigh-Jeans formula, which is an expression that attempts to give us the energy density u(ν,T) of radiation in the cavity, where ν is frequency and T is the temperature. Qualitatively, it is formed as a product of two quantities:
u = number degrees of freedom for frequency ν * average energy per degree of freedom"
The * means multiplication here. What does degree of freedom of frequency mean here?
Best Answer
I'm assuming that this section of the book is talking about the ultraviolet catastrophe, where an ideal black body in thermal equilibrium will emit an infinite amount of power through radiative means. The source goes on to say:
Following that:
Essentially, if in a cavity there are an infinite number of electromagnetic modes possible (think standing waves), the Equipartition Theorem says that a system in equilibrium has an average of $k_{b}T$ worth of energy per mode. This is not what's actually observed, since we don't see an infinite amount of power radiated. How was this solved: