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. Refraction is the change in the direction of a wave passing from one medium to another. Refraction of light is one of the most commonly observed phenomena, but other waves like sound waves and water waves also experience refraction.
Laws of refraction
When a beam of light passes through two different media via an interface, its behaviour is governed by the laws of refraction of light. These laws are also known as Snell’s law.
Two laws of refraction
The two laws followed by a beam of light traversing through two media are:
- The incident ray refracted ray, and the normal to the interface of two media at the point of incidence all lie on the same plane.
- The ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant. This is also known as Snell’s law of refraction.
sin i / sin r = n whereby n is the refractive index of the denser medium.
- Twinkling of stars is due to refraction of light.
- Mirage and looming are optical illusions which are a result of refraction of light.
- A swimming pool always looks shallower than it really is because the light coming from the bottom of the pool bends at the surface due to refraction of light.