- #1
ajayguhan
- 153
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How is the number of oscillations per unit volume in the frequency range of v and dv is
(8v^2*dv)c^3 where c is the velocity of light
(8v^2*dv)c^3 where c is the velocity of light
The Rayleigh-Jeans law is a formula that describes the spectral energy density of blackbody radiation. It was proposed by Lord Rayleigh and Sir James Jeans in the early 1900s and is valid only at long wavelengths.
The Rayleigh-Jeans law is derived by considering the classical theory of electromagnetic radiation, which states that a blackbody should emit radiation with a continuous spectrum. By applying this theory to the thermodynamic equilibrium of a blackbody, the Rayleigh-Jeans law can be derived mathematically.
There are two main assumptions made in deriving the Rayleigh-Jeans law: first, that the radiation is in thermal equilibrium with the walls of the blackbody; and second, that the energy of the radiation is proportional to the square of the amplitude of the electric field.
The Rayleigh-Jeans law is only valid at long wavelengths and fails to accurately describe the observed spectrum of blackbody radiation at shorter wavelengths. This discrepancy, known as the "ultraviolet catastrophe," was later resolved by Max Planck's quantum theory of radiation.
The Rayleigh-Jeans law is the classical limit of the Planck's law, which accurately describes the spectral energy density of blackbody radiation at all wavelengths. The Rayleigh-Jeans law also serves as a useful approximation in certain scenarios, such as when dealing with low-energy radiation or when calculating the average energy of a blackbody.