svartkroppsstrålnaren

Svartkroppsstrålning, often referred to as ideal black body radiation, is the electromagnetic radiation that an opaque object would emit if it were a perfect black body. A perfect black body is an idealized physical object that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence, and reflects none. It is also a perfect emitter. The spectrum of radiation emitted by a black body is dependent only on its temperature.

The theoretical concept of black body radiation was crucial in the development of quantum mechanics. Classical physics, specifically the Rayleigh-Jeans law, predicted that the intensity of radiation would increase indefinitely with frequency, leading to what was known as the "ultraviolet catastrophe." This prediction contradicted experimental observations, which showed that the intensity peaked at a certain frequency and then decreased.

Max Planck resolved this issue in 1900 by proposing that energy is not emitted or absorbed continuously, but in discrete packets called quanta. The energy of a quantum is proportional to the frequency of the radiation, given by the equation E = hf, where h is Planck's constant and f is the frequency. This quantization of energy successfully explained the observed black body spectrum and marked the birth of quantum theory.

The characteristics of black body radiation are described by Planck's law, which specifies the spectral radiance as a function of frequency and temperature. Wien's displacement law describes the relationship between the temperature of the black body and the wavelength at which its radiance is maximum. Stefan-Boltzmann law quantifies the total energy radiated per unit surface area of a black body across all wavelengths, which is proportional to the fourth power of its temperature.