from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. 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.
from the GNU version of the Collaborative International Dictionary of English
- n. Absorptiveness.
from The Century Dictionary and Cyclopedia
- n. The power or capacity of absorption.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. (physics) the property of a body that determines the fraction of the incident radiation or sound flux absorbed or absorbable by the body
The absorptivity is the fraction of incident light power that is absorbed by the body/surface.
Ice has a very high reflectivity and a very low absorptivity in the wavelengths of solar radiation.
The hint is that the absorptivity of the glass in the IR is roughly unity as is that of the black cardboard, and therefore their IR emissivity is also unity in the IR by Kirchoff's law.
Hycrete Admixtures transform concrete from an open network of capillaries and cracks into an ultra-low absorptivity, waterproof, protective building material.
This limit of absorptivity is important because some skeptics argue that, between water vapor and CO2, every available ray of IR within the absorption ranges of CO2 is already being absorbed.
Note that absorptivity and emissivity are properties of objects - they do not imply any particular absorption or emission.
This is independent whether we consider a black or a gray emitter because the special case of the absorptivity equal to unity is included.
It might be that you have recently recognized that absorptivity, emissivity and scattering is dependent on the wavelenght.
Thus a fresh whitewash surface has an absorptivity of about 0.12 for solar radiation but the absorptivity for longwave radiation from other surfaces at ordinary temperatures peak intensity 10Î¼ is about 0.95.
On the other hand, a polished metal has a very low absorptivity and emissivity for both solar radiation and longwave radiation.