RAY OPTICS AND OPTICAL INSTRUMENT - Refraction of Light

The binding of the X-ray of light passing from one medium to the other medium is called Refraction.

AO – Incident ray
OB – refracted ray
Angle i – Incident angle
Angle r – Refracted angle

Laws of Refraction: The ratio of the sign i of the angle of the incidence to the angle of refraction ( r) is a constant called refractive index.

¹n₂ is the refractive index of second medium. 

If first medium is air, then velocity of light (v = c) and velocity of light is second medium (v₂ = v)

¹n₂ = c / v (absolute refractive index)

Absolute refractive index 1^st medium

^an₂ = c / v₂

Refractive index of 2^nd medium with respect to 1^st medium

Second Law: The incident ray, refracted ray and the normal to the interface at the point of interface, all lie in same plane.