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Saturday, 31 October

JEE Main 2021 · PhysicsNumerical answerNumerical valueMediumMulti-step

JEE Main 3 August 2021, Shift 1, Physics Q30

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

A ray of monochromatic light is incident on one refracting face of prism of angle 75°. It passes through the prism and is incident on the other face at the critical angle. If the refractive index of the material of the prism is 2\sqrt{2} , the angle of incidence on the first face of the prism is _________. (degree).

Official answer

45

NTA final key.

Chapter
Ray Optics and Optical Instruments
Topic
Prism Deviation
Idea tested
TIR at Second Face Condition

Same idea in other shifts

Asked 2× in all
  1. 2 Apr 2026, Shift 2 · Q41One side of an equilateral prism is painted by a transparent material of refractive index n2n_2. The refractive index of prism is 1.6. The…MediumSingle correctHas a figure

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.