reflectancen.
/rᵻˈflɛkt(ə)ns/, U.S. /rəˈflɛkt(ə)ns/, /riˈflɛkt(ə)ns/ Physics.
The proportion of incident light which a substance or object reflects or scatters; spec. a complex number whose modulus is the proportion of the radiant flux (at specified wavelengths) which is reflected, and whose argument represents the change of phase undergone by the reflected light. Cf. reflection coefficient n., reflection factor n. at reflection n. Compounds 2.
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the world > matter > physics > electromagnetic radiation > light > reflection > [noun] > reflected light > proportion reflected
reflectance1893
reflection coefficient1912
reflection factor1919
reflectivity1936
1893 G. F. Fitzgerald & F. T. Trouton in Nature 14 Dec. 149/1 With a view of examining this system [of nomenclature], the following list is subjoined... Phenomenon... Reflection. Amount of... Reflectance.
1926 Jrnl. Optical Soc. Amer. 10 178 Reflectance..is the ratio of reflected to incident radiant energy.
1932 A. C. Hardy & F. H. Perrin Princ. Optics xi. 234 The high reflectance of chlorophyl gives foliage the appearance of intense local lighting.
1957 V. J. Kehoe Technique Film & Television Make-up viii. 96 Black velvet has approximately 2 per cent reflectance, while some white paper is as high as 90 per cent.
1960 Illuminating Engin. 55 228/1 The concepts of transmittance and reflectance can be extended to cover the separation of specular and diffuse components which are functions of angles.
1998 Gramophone Jan. 118/1 CD-RW discs, because of their lower reflectance, can be played only on CD-RW machines.
2007 Herald-Times (Bloomington, Indiana) 15 Mar. e9/1 The newly revised California Code of Regulations..establishes minimum levels of solar roof reflectance for construction in California.
Compounds
General attributive.
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1946 Life 3 June 24 (advt.) Colors that cool (determined by infra-red reflectance tests).
1956 Nature 14 Jan. 74/2 The assessment of particular reflectance characteristics of cotton.
1975 D. H. Burrin in Williams & Wilson Biologist's Guide to Princ. & Techniques Pract. Biochem. v. 138 Reflectance spectrophotometers..measure the radiation absorbed when a light beam is reflected by the sample.
1992 Lancet 27 June 1570/2 Reflectance spectrophotometry was used to measure peak acute skin reactions (erythema) at the time of radiotherapy.
2001 Proc. Royal Soc. B. 268 567/2 (caption) Mean reflectance spectra of eggs of the red-breasted cuckoo.
This entry has been updated (OED Third Edition, September 2009; most recently modified version published online March 2022).
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n.1893