Snell’s Law

Following are the laws of refraction of light:

1. Whenever light goes from one medium to another the velocity of light changes.
2. The incident ray, the refracted ray and the normal at the point of incidence, all lie in the same plane.
3. The ratio of sine of the angle of incidence to the sine of angle of refraction is constant for a given pair of media. This law is also known as Snell’s law.

                                 =    Constant

Here, the constant is also called refractive index and is represented by letter ‘n’. So,

                                 =    n

       Where, Sin i = Sine of the angle of incidence

                   Sin r = Sine of the angle of refraction

Test Your Understanding and Answer These Questions:

1. What is Snell’s law?
2. Give the laws of refraction of light.