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| In physics, the ultraviolet catastrophe , also called the Rayleigh-Jeans catastrophe, is the classical prediction, first made in the late 19th century, that an ideal black body A hypothetical object capable of absorbing all the electromagnetic radiation falling on it black body at thermal equilibrium will emit radiation with infinite power. As this is clearly shown by observation to be false, it was one of the first clear indications of problems with classical physics. In 1900, Max Plancks German physicist whose explanation of blackbody radiation in the context of quantized energy emissions initiated quantum theory (1858-1947) Max Planck's solution of this problem led to one of the early portions of quantum mechanics The branch of quantum physics that accounts for matter at the atomic level; an extension of statistical mechanics based on quantum theory (especially the Pauli exclusion principle) quantum mechanics . . |
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The Ultraviolet Catastrophe A blackbody is an idealized object which absorbs and emits all frequencies. Classical physics can be used to derive an equation which describes the intensity of blackbody radiation as a function of frequency for a fixed temperature--the result is known as the Rayleigh-Jeans law. Although the Rayleigh-Jeans law works for low frequencies, it diverges as Max Planck explained the blackbody radiation in 1900 by assuming that the energies of the oscillations of electrons which gave rise to the radiation must be proportional to integral multiples of the frequency, i.e.,
Using statistical mechanics, Planck derived an equation similar to the Rayleigh-Jeans equation, but with the adjustable parameter h . Planck found that for
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; this divergence for high frequencies is called the ultraviolet catastrophe. 
J s, the experimental data could be reproduced. Nevertheless, Planck could not offer a good justification for his assumption of energy quantization. Physicicsts did not take this energy quantization idea seriously until Einstein invoked a similar assumption to explain the photoelectric effect. 
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