{1 } The ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant

{2} incident ray, refracted ray and normal lie in the same plane

Refraction is the bending of a wave when it passes from one medium to another. The bending is caused due to the differences in density between the two substances.

Refractive index, also called the index of refraction describes how fast light travels through the material.

Mirages

Formation of a rainbow

light passes through a prism

magnification through a lense

Spectacles worn by people with defective vision

peepholes of house doors, cameras, movie projectors and telescopes.