Question

The refractive index of a glass is 1.520 for red light and 1.525 for blue light. Let D₁ and D₂ be angles of minimum deviation for red and blue light respectively in a prism of this glass. Then,
(a) D₁ < D₂
(b) D₁ = D₂
(c) D₁ can be less than or greater than D₂ depending upon the angle of prism
(d) D₁ > D₂

Answer 1

(a) For a thin prism, D = (μ – 1) A Since λ_b < λ_r ⇒ μ_r < μ_b ⇒ D₁ < D₂