blackbody

blackbody

Theoretical surface that absorbs all radiant energy that falls on it, and radiates electromagnetic energy at all frequencies, from radio waves to gamma rays, with an intensity distribution dependent on its temperature. Because all visible light falling on such a surface is absorbed without reflection, the surface will appear black as long as its temperature is such that its emission peak is not in the visible portion of the spectrum. See also absorption.

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blackbody [′blak¦bäd·ē]

(thermodynamics)

An ideal body which would absorb all incident radiation and reflect none. Also known as hohlraum; ideal radiator.

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Blackbody

An ideal energy radiator, which at any specified temperature emits in each part of the electromagnetic spectrum the maximum energy obtainable per unit time from any radiator due to its temperature alone. A blackbody also absorbs all the energy which falls upon it. The radiation properties of real radiators are limited by two extreme cases—a radiator which reflects all incident radiation, and a radiator which absorbs all incident radiation. Neither case is completely realized in nature. Carbon and soot are examples of radiators which, for practical purposes, absorb all radiation. Both appear black to the eye at room temperature, hence the name blackbody. Often a blackbody is also referred to as a total absorber. See Heat radiation

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blackbody

1. A body whose radiation at each wavelength is the maximum possible for any electromagnetic radiator at that temperature.

2. A body that absorbs all light which is incident on it and consequently looks black.