Black body radiation

Wikipedia
"An object that absorbs all radiation falling on it, at all wavelengths, is called a black body. When a black body is at a uniform temperature, its emission has a characteristic frequency distribution that depends on the temperature. Its emission is called black-body radiation.

The concept of the black body is an idealization, as perfect black bodies do not exist in nature. Graphite and lamp black, with emissivities greater than 0.95, however, are good approximations to a black material. Experimentally, black-body radiation may be established best as the ultimately stable steady state equilibrium radiation in a cavity in a rigid body, at a uniform temperature, that is entirely opaque and is only partly reflective. A closed box of graphite walls at a constant temperature with a small hole on one side produces a good approximation to ideal black-body radiation emanating from the opening."

helped establish the foundations of quantum mechanics



Plank's law , Stefan–Boltzmann law , Einstein , quantum dynamics Cosmic_microwave_background_radiation

Radiated power per square meter : P = σ T4 [ W per m² ]



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Zig Herzog; hgnherzog@yahoo.com

Last revised: 04/11/13