Chapter-9|Ray Optics and Optical Instrument|NCERT 12th Physics:
A Prism is a portion of a transparent medium bounded by two plane faces inclined to each other at suitable angle.
Refraction of Light Through a Prism:
Lat us consider a triangular prism ABC.
Let angle of incidence and angle of refraction at first phase AB are i and r₁
The angle of incidence at the second face AC is r₂ and the angle of emergence is e.
The angle between emergence Ray RS and incident ray PQ is called angle of deviation δ.
If μ is the refractive index of material of the prism, Then according to Snell’s law-
This is the angle through which a ray deviates on passing through the thin prism of small refracting angle A.