A ray of light is incident at 45° on a refracting surface of a prism. The angle of prism is 60°. If the ray suffers minimum deviation through the prism, the angle of minimum deviation and refractive index respectively are:
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Question

A ray of light is incident at 45° on a refracting surface of a prism. The angle of prism is 60°. If the ray suffers minimum deviation through the prism, the angle of minimum deviation and refractive index respectively are:

Options

G1 Physics · Accepted Answer

Step 1: At minimum deviation, incident and emergence angles are equal: i = e = 45°. Step 2: Prism deviation δₘ = i + e − A = 45° + 45° − 60° = 30°. Step 3: Symmetric path r₁ = r₂ = A/2 = 30°. Refractive index μ = sin i/sin r₁ = (√2/2)/(1/2) = √2. Final answer: (A) 30°, √2.