The relationship between absorbtion, emissivity and reflection

by swampwiz
Tags: absorbtion, emissivity, reflection, relationship
swampwiz is offline
May29-12, 09:55 PM
P: 58
As I understand it, the absorption coefficient of a surface of material is the same as its emissivity (due to Kirchoff's law of thermal radiation), and that the net of this and the tranmissibility is

emissivity + reflectivity + transmissibility = 1

Is this a general statement about any radiation, or only about thermal "black-body" radiation?

I presume that the tranmissibility is the initial transmissibility of the surface, since once inside the body of the material, there is absorbtion, which is termed attenuation, in which the transmitted radiation is slowly absorbed as it goes through the body. How are these 2 forms of absorbtion related?
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Andy Resnick
Andy Resnick is offline
May30-12, 08:22 AM
Sci Advisor
P: 5,468
That is a general statement, and a consequence of conservation of energy.

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