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In other fields, the dispersion can be a nuisance: in camera lenses it leads to chromatic aberration and in optical cables chromatic dispersion limits the maximum bandwidth of the fiber (though this effect is not as strong as modal dispersion which is caused by longer paths of reflected rays as opposed to those that travel straight through along the core.
Further Reading/Watching
1. The speed of light in a glass
Refraction:
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It’s the change in direction |
of a [wave|http://en.wikipedia.org/wiki/Wave] due to a change in its [medium|http://en.wikipedia.org/wiki/Optical_medium]. It is essentially a surface phenomenon. This is most commonly observed when a wave passes from one [medium|http://en.wikipedia.org/wiki/Optical_medium] to another at any angle other than 90° or 0°.\[1\] |
Explanation:
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Refraction of [light|http://en.wikipedia.org/wiki/Light] is the most commonly observed phenomenon, but any type of wave can refract when it interacts with a medium, for example when [sound waves|http://en.wikipedia.org/wiki/Sound_wave] pass from one medium into another or when water waves move into water of a different depth\[1\]. With light, the speed in transparent medium is lower than in vacuum since light can travel in vacuum and doesn’t need a medium to travel. |
We characterize the transparent medium by its *Index of Refraction*, defined as the ratio of the speed of light c in vacuum to the speed on light in the medium:
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n=c/v (index of refraction) eq….1 \[2\] |
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After comparing equation 1 and 2 we get λ=c/nf and since c and f don’t change, the wavelength is inversely proportional to n.
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Refraction is described by [Snell's law|http://en.wikipedia.org/wiki/Snell%27s_law], which states that for a given pair of media and a wave with a single frequency, the ratio of the sines of the [angle of incidence|http://en.wikipedia.org/wiki/Angle_of_incidence] _θ{_}{_}{~}1{~}_ and [angle of refraction|http://en.wikipedia.org/wiki/Angle_of_refraction] _θ{_}{_}{~}2{~}_ is equivalent to the ratio of phase velocities (_v{_}{_}{~}1{~}{_}_ / v{_}{_}{~}2{~}_) in the two media, or equivalently, to the opposite ratio of the indices of refraction (_n{_}{_}{~}2{~}{_}_ / n{_}{_}{~}1{~}_)\[1\]:
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Going from a medium of lower refractive index, to a medium of higher refractive index, the beam bends toward the normal. In opposite case, when light travels from a higher refractive index to lower refractive index, the beam bends away from the normal. \\ !brokpen.jpg|border=1!\[3\] |
Further Reading/Watching
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References:
1.http://en.wikipedia.org/wiki/Refraction
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