A light ray is incident perpendicular to one face of a 90° prism and is totally internally reflected at the glass-air interface. If the angle of reflection is 45°, we conclude that the refractive index n :

Question

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 n > √2. Therefore the correct option is B.