Refraction of Light Formula
In all media the light does not travelled in same direction.
The incident ray, refracted ray & normal in any two medium lie on the same plane. The law of refraction is also known as snell’s law of refraction.
From above figure, the direction of light ray is changed at O and O’ NN’ and MM’ is the normal drawn perpendicular to PQ and RS respectively. The light ray pass from denser medium to rarer medium, i.e. from air to glass.
In fig (i) AO is incident on surface PQ the ray AO is called incident ray OO’ is refracted ray and O’D is emergent ray. Thus the emergent ray O’D is parallel to the incident ray. In fig (i) The two refraction is occurs. In 1st refraction the light ray enters glass from air at O on sides PQ. Whereas in 2nd refraction the light ray enters air through glass at O’ on side SR (i) is angle of incidence in 1st case and i1 is angle of incidence in second case.
So, i1 = r
The angle of refraction is equal to the angle of incidence.
Laws of refraction:
(1) The incident ray, the refracted ray and normal of two media lie on the same plane.
(2) The ratio on sine of angle of incidence to sine of angle refraction is constant.
So, Sin i/Sin r = constant
i = angle of incidence
r = angle of refraction