JEE Main 2021 · PhysicsMultiple choiceSingle correctMediumMulti-step

JEE Main 4 August 2021, Shift 1, Physics Q7

Question 7 of 90 in this shift, Physics question 7 of 30, Section A.

The refractive index of a prism is 1.6. When prism is immersed in a liquid of 1.2 refractive index, then the change in the angle of minimum deviation will be ________. (Assume prism is equilateral) Given

\sin^{-1}\left(\frac{4}{5}\right) = 53^\circ

\sin^{-1}\left(\frac{2}{3}\right) = 41^\circ

(1) $19.8^\circ$
(2) $16.2^\circ$
(3) $36^\circ$
(4) $24^\circ$ Official answer

Official answer

Option 4

NTA final key.

Chapter: Ray Optics and Optical Instruments
Topic: Prism Deviation
Idea tested: Prism in Surrounding Medium

Same topic in other shifts

All Prism Deviation questions

2 Apr 2026, Shift 1 · Q40For a thin symmetric prism made of glass (refractive index $1.5$ ), the ratio of incident angle and minimum deviation will be _________.MediumSingle correct
2 Apr 2026, Shift 2 · Q41One side of an equilateral prism is painted by a transparent material of refractive index $n_2$ . The refractive index of prism is 1.6. The…MediumSingle correctHas a figure
5 Apr 2026, Shift 1 · Q40A ray of light passing through an equilateral prism is having velocity $2.12 \times 10^8$ m/s in the prism material, then the minimum…MediumSingle correct
6 Apr 2026, Shift 2 · Q42Angle of minimum deviation is equal to the half of the angle of prism in an equilateral prism. The refractive index of the prism is…EasySingle correct
2 Apr 2025, Shift 2 · Q49A ray of light suffers minimum deviation when incident on a prism having angle of the prism equal to $60^\circ$ . The refractive index of…EasyNumerical value
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 108 of the 174 JEE Main shifts held from 2017 to 2026.