Quantum mechanics
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Abstract
The Ultra Violet Catastrophe In blackbody spectra, the spectral distribution of energy in the radiation depends only on the temperature of the body. Why does the blackbody spectrum have the shape it has? Lord rayleigh and James Jean considered the radiation inside a cavity of absolute temperature T whose walls are perfect reflectors to be a series of standing electromagnetic waves. This is a three dimensional generalization of standing waves in a stretched string. The condition for standing waves in such a cavity is that the path length from wall to wall, whatever the location, must be a while number of halfwavelengths, so that a node occurs at each reflecting surface. The number of independent standing waves G(f)df in the frequency interval between f and df per unit volume in the cavity turned out to be G(f)df = 8Ï€fdf c3 (2.1)