A ray of light is incident normally on one of the faces of a prism of apex angle 30° and refractive index 2 . The angle of deviation of the ray is -
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Question

A ray of light is incident normally on one of the faces of a prism of apex angle 30° and refractive index 2 . The angle of deviation of the ray is -

G1 Physics · Accepted Answer

Derived solution: Step 1: For a prism use r₁ + r₂ = A and δ = i + e - A. At minimum deviation i = e and r₁ = r₂ = A/2, so μ = sin[(A + δₘ)/2]/sin(A/2). Step 2: Substitute the values given in the question and apply the geometry/sign convention shown. Step 3: On simplification the result is 15°. Therefore the correct option is C.