a measure of the rate of decrease in the intensity of electromagnetic radiation (as light) as it passes through a given substance; the fraction of incident radiant energy absorbed per unit mass or thickness of an absorber;
"absorptance equals 1 minus transmittance"
双语例句
The absorption coefficient is often strongly wavelength-dependent. 吸收系数往往与波长密切相关。
Therefore, at sufficiently high energies the absorption coefficient begins to increase after passing through a minimum. 因此，在足够高的能量下，吸收系数便由最小值开始增加。
