The refractive index of a prism with apex angle $A$ is $\cot A/2$. The angle of minimum deviation is :

Option 1: $\delta_m=180^\circ-2A$

JEE Main 2024 · PhysicsMultiple choiceSingle correctMediumApplication

JEE Main 31 January 2024, Shift 1, Physics Q45

Question 45 of 90 in this shift, Physics question 15 of 30, Section A.

The refractive index of a prism with apex angle

A

\cot A/2

. The angle of minimum deviation is :

(1) $\delta_m=180^\circ-2A$ Official answer
(2) $\delta_m=180^\circ-3A$
(3) $\delta_m=180^\circ-4A$
(4) $\delta_m=180^\circ-A$

Official answer

Option 1

NTA final key.

Chapter: Ray Optics and Optical Instruments
Topic: Prism Deviation
Idea tested: Minimum Deviation Condition

Same idea in other shifts

Asked 4× in all

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3 Apr 2025, Shift 1 · Q41Consider following statements for refraction of light through prism, when angle of deviation is minimum. A. The refracted ray inside prism…MediumOther

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 42 of the 174 JEE Main shifts held from 2017 to 2026.