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Absorption coefficient

The absorption coefficient α is a property of a material. It defines the extent to which a material absorbs energy, for example that of sound waves or electromagnetic radiation. Wallace Sabine was a pioneer of this concept in acoustics and defined the unit of the Sabine. A Sabine is defined as a fraction of acoustic power absorbed by a 1m square of open window. In SI units, absorption coefficient is measured in inverse metres, and is represented by the Greek letter α.

Additional recommended knowledge

Sound Absorption Coefficients for Some Common Materials - This website helps one understand the concept as well as provides formulae and some coefficients.

In chemistry and biological sciences, the absorption coefficient is a measure of the solubility of a gas in a liquid measured as the volume of the gas (taken under standard conditions) that saturates a unit volume of the liquid.

Absorption coefficient is sufficient for describing energy propagation through a homogeneous system only. Propagation through a heterogeneous system is affected by scattering,[1]. There is more general term attenuation that takes into account both absorption and scattering. It is widely used in acoustics as attenuation coefficient for characterizing particle size distribution. [2],[3].

See also


  1. ^ Bohren,C. F. and Huffman, D.R. "Absorption and Scattering of Light by Small Particles", Wiley, (1983), isbn= 0-471-29340-7
  2. ^ Dukhin, A.S. and Goetz, P.J. "Ultrasound for characterizing colloids", Elsevier, 2002
  3. ^ ISO 20998-1:2006 "Measurement and characterization of particles by acoustic methods"
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Absorption_coefficient". A list of authors is available in Wikipedia.
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