What is black body radiation?

Black body radiation refers to the electromagnetic radiation emitted by an idealized object known as a black body, which is defined as a perfect emitter and absorber of radiation across all wavelengths. This theoretical object absorbs all incident radiation without reflecting any, and as a result, it emits radiation in a characteristic spectrum that depends only on its temperature.

The key aspects of black body radiation include its dependence on temperature and the fact that it serves as a standard against which real emitters can be measured. The spectrum of radiation emitted by a black body shifts with temperature, described by Planck's law, indicating that higher temperatures lead to higher intensity and shorter wavelengths of emitted radiation.

Understanding black body radiation is foundational in multiple areas of physics, particularly in thermodynamics and quantum mechanics, as it illustrates the principles of thermal emission and energy distribution.