Rayleigh-Jeans law

In physics, Rayleigh-Jeans Law, first proposed in the 19th century, expresses the energy density of blackbody radiation of wavelength λ as

where λ is in meters, T is the temperature in Kelvins, and k is Boltzmann's constant.

The law agrees with experimental measurements for long wavelengths but disagrees for short wavelengths.

Max Planck revised the law, which states:

where h is Planck's constant, c is the speed of light.