Absorption of light as it passes through matter results in a decrease in intensity. Absorption, like scattering, may be general or selective. Selective absorption gives the world most of the colors we see. Glass filters which absorb part of the visible spectrum are used in research and photography. An absorption curve for a filter shows the amount of light absorbed at a particular wavelength. A unit thickness of the absorbing medium will always absorb the same fraction of light from a beam. If the first millimeter thickness of a filter absorbs 1/2 the light, the second millimeter absorbs 1/2 the remaining light, or 1/4 of the total. The third millimeter absorbs 1/2 of the 1/4, so only 1/8 of the light is transmitted through three millimeters of filter . . . . [p. 51] [Light and Color, by Clarence Rainwater, Prof. of Physics, San Francisco State College, Original Project Editor Herbert S. Zim, Golden Press, NY, Western Publishing Company, Inc., 1971.]
R E F E R E N C E S
Absorption n [F & L; F, fr. L absorptin-, absorptio, fr. absorbére] [1741] 1a: the process of absorbing or of being absorbed -compare Absorption b: interception of radiant energy or sound waves 2: entire occupation of the mind [__ in his work]
Absorb vt [MF absorber, fr. L absorbére, fr. ab- + sorbére to suck up; akin to Lith surbiti to sip, Gk rophein to gulp down] [15c] 1: to take in and make part of an existent whole [the capacity of China to __ invaders] 2a: to suck up or take up [a sponge __s water] [charcoal __s gas] [plant roots __ water] b: to take in: Acquire, Learn [convictions __ed in youth -M.R. Cohen] c: Use Up, Consume [the fever __ed her strength] 3: to engage or engross wholly [__ed in thought] 4a [1]: to receive without recoil or echo [provided with a sound-absorbing surface] [2]: Endure, Sustain [__ing hardships] [3]: Assume, Bear [the expenses were __ed by the company] b: to transform [radiant energy] into a different form usu. with a resulting rise in temperature [the earth --s the sun's rays]
[Merriam-Webster's Collegiate Dictionary, 10th Edition. Springfield, MA, USA: Merriam-Webster, Inc. 1995.]
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