State the laws of refraction

Explanation

(i) The incident ray and refracted ray are on the opposite sides of the normal at the point of incidence and all three lie in the same plane.
(ii) For a given pair of media, the ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant.
If 'i' is the angle of incidence and 'r' is the angle of refraction, then `(sin i)/(sin r)=` constant
This constant is called refractive index of a medium.