What law does black body radiation obey?

Black body radiation is fundamentally described by Planck's law, which provides a theoretical framework explaining how idealized objects, known as black bodies, emit radiation based on their temperature. According to this law, the intensity and spectral distribution of the emitted radiation depend solely on the temperature of the black body and are not influenced by its surface properties or material composition.

Planck’s law gives a precise mathematical relationship between the energy emitted and frequency (or wavelength) of the radiation, showing that at higher temperatures, the peak wavelength of the emitted radiation shifts to shorter wavelengths. This relationship is crucial for explaining phenomena associated with thermal radiation and allows us to predict the behavior of real-world objects that approximate ideal black bodies.

Understanding Planck's law is essential in various fields, including thermodynamics, quantum mechanics, and astrophysics. It addresses inconsistencies that arise from classical physics, such as the ultraviolet catastrophe, and sets the foundation for quantum theory. Thus, Planck’s law is the correct context for discussing black body radiation.