For an isosceles prism of angle A and refractive index μ, it is found that the angle of minimum deviation δₘ = A. Which of the following options is/are correct?
Select all that apply

Question

For an isosceles prism of angle A and refractive index μ, it is found that the angle of minimum deviation δₘ = A. Which of the following options is/are correct?

G1 Physics · Accepted Answer

At minimum deviation, i = e and r₁ = r₂ = A/2. Given δₘ = A, δₘ = 2i - A gives i = A, so r₁ = A/2 = i₁/2; hence A is correct. Also μ = sin A/sin(A/2) = 2 cos(A/2), so the correct relation is A = 2 cos⁻¹(μ/2), not A = (1/2) cos⁻¹(μ/2); hence B is incorrect. For grazing emergence, μ sin r₂ = 1 and r₁ + r₂ = A. Combining this with Snell's law at the first face gives i₁ = sin⁻¹[sin A √(4 cos²(A/2) - 1) - cos A]; hence C is correct. For i₁ = A, the internal ray is parallel to the base; hence D is co…