Snell's law

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Snell's law:

see refractionrefraction,
in physics, deflection of a wave on passing obliquely from one transparent medium into a second medium in which its speed is different, as the passage of a light ray from air into glass.
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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Snell’s Law


a law governing the refraction of a beam of light at the boundary between two transparent media. It asserts that the ratio sin α /sin β is constant for the same two media; here, α is the angle of incidence of the beam on the boundary, and β is the angle of refraction.

The law was established by W. Snell around 1620 and by R. Descartes in 1637. The discovery of Snell’s law permitted the completion of the foundations of geometrical optics and made possible the formulation of Fermat’s principle. The law provided the basis for the introduction of the concept of the refractive index of a medium. In terms of refractive indexes, Snell’s law can be written in the form sin α/sin β = n2/n1 where n1 and n2 are the refractive indexes of the first and second media, respectively, through which the light travels. (See alsoREFRACTION OF LIGHT.)

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Based on the derivation above, the angle calculation problem is transformed to root finding problem for polynomial, as there will be no trigonometric function of Snell's law. Equation can be further reduced taking advantage of fact that S, P, T points always have some distance between them; we can drop denominator after simplifying fractions from (6)
As Snell's Law enables us to define the device's light guide geometry, it is necessary to have a starting point that is when the system is in equilibrium, input of light energy into the light guide is equal to the output energy from the light guide.
Cui, "An ultrathin directional carpet cloak based on generalized Snell's law," Appl.
The wave vector of the refracted wave can be calculated by using Snell's Law of refraction.
Snell's Law, Available from: Accessed: 2009-06-25
Refraction To measure the Perspex Graph paper and refractive index of a Protractor Torch reflection transparent substance CD Cardboard using Snell's Law. Template Scissors/ To construct a CD Stanley knife spectroscope Sticky tape (Wakabayashi et al.
By measuring the angles that light enters and leaves a substance, and using Snell's law, the refractive index of the sample can be calculated.
It is not difficult to understand this consequence if we note that y = csc [theta], where [theta] is the incident angle of the ray, and d is the wave front distance satisfying Snell's law. When d, [[alpha].sub.1], [k.sub.1], and [k.sub.2] are given, we have a group of specified rays that have the same arrival time t satisfying Eq.