# Absorptivity

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Related to Absorptivity: Molar absorptivity

## absorptivity

[əb‚sȯrp′tiv·əd·ē]
(analytical chemistry)
The constant a in the Beer's law relation A = abc, where A is the absorbance, b the path length, and c the concentration of solution. Also known as absorptive power. Formerly known as absorbency index; absorption constant; extinction coefficient.
(thermodynamics)
The ratio of the radiation absorbed by a surface to the total radiation incident on the surface.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

## Absorptivity

(or absorptive power), αv, the fraction of a monochromatic radiation flux of frequency v that is absorbed by a body on which the flux is incident. Although often called the absorption factor, it differs from the absorption factor in that it applies only to radiation of a specific frequency. The absorption factor is the integral of the absorptivities over all the frequencies present in the irradiating flux. The absorptivity for thermal radiation is dependent not only on the frequency or wavelength of the radiation but also on the temperature T of the body:

α = α(ν, T) = α*(λ, T)

### REFERENCE

Landsberg, G. S. Optika, 4th ed. Moscow, 1957. (Obshchii kurs fiziki, vol. 3.)
References in periodicals archive ?
Caption: Figure 8: (a) Simulated absorptivity for different incidence angles for TE (a) and TM (b) polarizations.
The SSM used in this study has fixed values of solar absorptivity of 0.1 and IR emissivity of 0.9.
Measurement of the UV/VIS Spectra and the Molar Absorptivity of Absorption Bands of [C.sub.76]-[D.sub.2].
where [alpha] is the absorptivity, R is the reflectance, and t is the transmittance of the surface.
where [A.sub.1] is N[H.sub.2] band area at 5060 [cm.sup.-1], [c.sub.pa1] is N[H.sub.2] concentration (mol/kg) and [[alpha].sub.pa1] is molar absorptivity of N[H.sub.2] band at 5060 [cm.sup.-1] that was quantified as 1.9213 kg/mol from the control 3,3'-DDS monomer spectrum at a sample thickness 0.20 mm.
Matavosian, "Scaling rules for total absorptivity and emissivity of gases," Journal of Heat Transfer, vol.
Beer's law was obeyed over the range of 5-50 [micro]g/mL; high values of molar absorptivity and low values of Sandell's sensitivity and LOD revealed that proposed methods are highly sensitive.
The radiant heat flux of fire will be transferred to the surface of a structure by absorptivity ratio of the surface while the structure emits the radiant heat flux in proportion to its emissivity .
The assay of HEMA in fresh and polymerized solutions was carried out by mixing a small amount of the solution with 0.05 M phosphate buffer, pH 7.0, and measurement of absorbance at 208 nm (molar absorptivity 8000 [M.sup.-1] [cm.sup.-1]).
Comparison of characteristic features of some spectrophotometric methods reported earlier for the determination of copper reveals the suitability of the present work in terms of molar absorptivity, linear range, interferences, LOD, and so forth (Table 5).

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