State the Snell’s laws of refraction of light.

The Snell’s laws of refraction of light are: (i) The incident ray, the refracted ray and the normal at the point of incidence, all lie in the same plane. (ii) The ratio of the sine of the angle of incidence i to the sine of the angle of refraction r is constant for the pair of given media. The constant 1 μ 2 is called the refractive index of the second medium with respect to the first medium.