Physics: Snell's law

Physics: Snell's law
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Electromagnetism Optics
Snell's law Snell's law (also known as the Snell–Descartes law, and the law of refraction) is a formula used to describe the relationship between the angles of incidence and refraction, when referring to light or other waves passing through a boundary between two different isotropic media, such as water, glass, or air.

Commentary

Commentary

Source: Wikipedia
Snell's law Snell's law (also known as the Snell–Descartes law, and the law of refraction) is a formula used to describe the relationship between the angles of incidence and refraction, when referring to light or other waves passing through a boundary between two different isotropic media, such as water, glass, or air.

Commentary

Source: Internal
Why does Snell's law matter? This principle is one of the building blocks physicists use to explain the world. Without it, a whole class of phenomena would have no mathematical description. Engineers, chemists, and astronomers all rely on it. sin ⁡ θ 1 sin ⁡ θ 2 = n 2 , 1 = n 2 n 1 = v 1 v 2 {\displaystyle {\frac {\sin \theta _{1}}{\sin \theta _{2}}}=n_{2,1}={\frac {n_{2}}{n_{1}}}={\frac {v_{1}}{v_{2}}}}

Commentary

Source: Wikipedia
Background: Snell's law Snell's law (also known as the Snell–Descartes law, and the law of refraction) is a formula used to describe the relationship between the angles of incidence and refraction, when referring to light or other waves passing through a boundary between two different isotropic media, such as water, glass, or air. In optics, the law is used in ray tracing to compute the angles of transmission or refraction, and in experimental optics to find the refractive index of a material. The law is also satisfied in meta-materials, which allow light to be bent "backward" at a negative angle of refraction with a negative refractive index. The law states that, for a given pair of media, the ratio of the sine s of angle of incidence ( θ 1 ) {\displaystyle \left(\theta _{1}\right)} and angle of refraction ( θ 2 ) {\displaystyle \left(\theta _{2}\right)} is equal to the refractive index of the second medium with regard to the first ( n 2 , 1 {\displaystyle n_{2,1}} ) which is equal to the ratio of the refractive indices ( n 2 n 1 ) {\displaystyle \left({\tfrac {n_{2}}{n_{1}}}\right)} of the two media, or equivalently, to the ratio of the phase velocities ( v 1 v 2 ) {\displaystyle \left({\tfrac {v_{1}}{v_{2}}}\right)} in the two media. sin ⁡ θ 1 sin ⁡ θ 2 = n 2 , 1 = n 2 n 1 = v 1 v 2 {\displaystyle {\frac {\sin \theta _{1}}{\sin \theta _{2}}}=n_{2,1}={\frac {n_{2}}{n_{1}}}={\frac {v_{1}}{v_{2}}}} The law follows from Fermat's principle of least time, which in turn follows from the propagation of light as waves.