The refraction of light occurs according to the following laws which are as follows.

1. The incident ray refracted ray, and the normal to the surface separating two media at the point of incidence all lie in the same plane.

2. The ratio of sine of angle of incidence and sine of angle of refraction remains constant ( = constant) subject to certain conditions. This law is called Snell’s law of refraction.

Refractive index of a medium (μ) =

⇒ μ =