black body radiation

In physics, Black-body radiation may refer to:Black body, an object that emits light (black-body radiation)Planck's law of black-body radiation, Intensity vs. Wavelength and TemperatureStefan-Boltzmann law of black-body radiation, Total Intensity vs. Temperature
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For a general introduction, see black body.In physics, Planck's law describes the spectral radiance of electromagnetic radiation at all wavelengths from a black body at temperature . As a function of frequency , Planck's law is written as: As a function of wavelength λ it is written (for infinitesimal solid angle) as:
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Noun
1. the electromagnetic radiation that would be radiated from an ideal black body; the distribution of energy in the radiated spectrum of a black body depends only on temperature and is determined by Planck's radiation law
(synonym) blackbody radiation
(hypernym) electromagnetic radiation, electromagnetic wave, nonparticulate radiation

The radiation emitted after a perfect absorber reaches a temperature which is higher than that of its surroundings. Black (or full) body radiation covers the entire electromagnetic spectrum with the peak emission taking place at a wavelength which is dependent only on the emitting body's temperature; see Wien's law . A perfect absorber does not reflect any electromagnetic radiation which falls upon it. All radiation is absorbed and converted into internal energy, or heat, as it is commonly known. It then re-radiates that heat energy as black body radiation. Perfect absorbers are often referred to as black bodies since anything black will tend to absorb radiation rather than reflect it. A close approximation is a very small hole into a constant temperature cavity, such as the human eye. The radiation emitted from stars approximates to that of a black body. This is why the colour of a star, which corresponds to its peak emission, can be used to determine its effective temperature.