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Snell's law

[snelz] /snɛlz/
noun, Optics.
the law that, for a ray incident on the interface of two media, the sine of the angle of incidence times the index of refraction of the first medium is equal to the sine of the angle of refraction times the index of refraction of the second medium.
named after Willebrod Snell van Royen (died 1626), Dutch mathematician Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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British Dictionary definitions for snells-law

Snell's law

(physics) the principle that the ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant when a light ray passes from one medium to another
Word Origin
C17: named after Willebrord Snell (1591–1626), Dutch physicist
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
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Encyclopedia Article for snells-law

Snell's law

in optics, a relationship between the path taken by a ray of light in crossing the boundary or surface of separation between two contacting substances and the refractive index (q.v.) of each. This law was discovered in 1621 by the Dutch astronomer and mathematician Willebrord van Roijen Snell (1580-1626; also called Snellius). The account of Snell's law went unpublished until its mention by Christiaan Huygens in his treatise on light.

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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