The refraction of light meets the following two law –
(sin i /sin r) = 1μ2
The refractive index has no unit as it is the ratio of two similar quantities.
When a light ray refracted from a denser medium to lighter medium, then the incidence angle of a denser medium reaches a certain critical value, such that the refracted angle will be 90°, that is refracted ray lies along the boundary. This certain value of the incidence angle is known as the critical angle of those mediums.
If light ray meets the following conditions then a critical angle can produce
The critical angle depends on the color of the light ray and the pair of the mediums. The critical angle of the red ray is greater than the green or a violet rays for a constant pair of the medium.
When a light ray refracted from a denser medium to lighter medium and incidence angle is greater than critical angles (i>θ), then the refracted angle will be greater than 90° and the refracted ray will return back to the denser medium. This phenomenon is known as total internal refraction.
If light ray meets the following conditions then total internal reflection can produce