The Snell's laws of refraction are:
1. The incident ray, the refracted ray and the normal at the point of incidence, all lie in the same plane.
2. The ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant for the pair of the given media.
sini/sinr = 1μ2
where 1μ2 is known as the refractive index of the second medium with respect to the first medium.
