An ideal black body is:

Explanation

A black body absorbs all incident radiation without reflecting or transmitting any of it. It emits radiation across a broad spectrum of frequencies based solely on its temperature. This emission follows Planck's law. The absorptivity of a black body is the same for all wavelengths and angles of incidence. The emitted radiation spectrum is continuous and depends on the temperature of the black body. Warmer black bodies emit more radiation, and the peak of the emission shifts to shorter wavelengths with increasing temperature. The intensity (brightness) of radiation emitted by a black body is directly proportional to the fourth power of its absolute temperature, as described by the Stefan-Boltzmann law. These characteristics are theoretical ideals, and while no real object perfectly meets these criteria, certain objects, like stars or specially designed cavities, can approximate the behavior of a black body under specific conditions.