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| Laws of Refraction |
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 The incident ray, the refracted ray and the normal to the surface at the point of incidence all lie in one plane. |
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 For any two given pair of mediums, the ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant. |
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| The above law is called Snell's law after the scientist Willebrod Snellius who first formulated it |
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| Where m is the refractive index of the second medium with respect to the first medium. |
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| We know that the phenomenon of refraction is taking place because the speed of light changes when it is
traveling from one optical medium to another. |
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| Thus we can define refractive index in terms of the speed of light in the two media. |
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| The refractive index of glass with respect to air is given by the relation. |
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| Refraction of Light |
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| In general, if a ray of light is passing from medium 1 to medium 2, then |
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| If the medium 1 is air or vacuum, the refractive index of medium 2 is referred to as the absolute refractive index. |
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| The refractive index of a medium depends on the following factors: |
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 the nature of the medium |
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 the
color or wave length of the incident light |
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