Question

Using the curve of angle of deviation and incidence how do you infer that the angle of minimum deviation is unique for a given light

Answer 1

For a parallel glass slab,

∆= I-R

Where, ∆= angle of deviation

I= angle of incidence

R= angle of refraction

For a Prism,

∆= I+i-A

Where, i= angle of emergence

A= angle of prism

And for the minimum angular deviation in a prism, the angle of incidence must be equal to the angle of emergence.