Question

How does the angle of minimum deviation of a glass prism vary, if the incident violet light is replaced by red light? Give reason.

Answer 1

(δ_m)_Violet > (δ_m)_red

We know that

λ_red > λ_violet

Since λ ∝ \(\frac{1}{\mu}\)

So µ_red < µ_violet

As µ = \(\frac{sin \frac{A+\delta_m}{2}}{sin A/2}\)

So (δ_m)_red < (δ_m)_violet

or (δ_m)_violet > (δ_m)_red.