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The angle of deviation through a prism is minimum when
(A) incident ray and emergent ray are symmetric to the prism
(B) the refracted ray inside the prism becomes parallel to its base
(C) angle of incidence is equal to that of the angle of emergence
(D) when angle of emergence is double the angle of incidence.

Asked in JEE Main 16th March 1st Shift 2021 · Deviation and minimum deviation

Answer: (3) Statements (A), (B) and (C) are true.

Step-by-step solution

At minimum deviation i = e and r₁ = r₂, so (C) is true.

This makes the path symmetric about the bisector of the prism angle, so (A) is true.

The ray inside is then parallel to the base, so (B) is true.

(D) contradicts i = e, so it is false.

Why the other options are wrong

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