JEE Main 2021 · PhysicsMultiple choiceSingle correctEasyApplication

JEE Main 25 July 2021, Shift 1, Physics Q9

Question 9 of 90 in this shift, Physics question 9 of 30, Section A.

A ray of laser of a wavelength 630 nm is incident at an angle of

30^\circ

at the diamond-air interface. It is going from diamond to air. The refractive index of diamond is 2.42 and that of air is 1. Choose the correct option.

(1)angle of refraction is $24.41^\circ$
(2)angle of refraction is $30^\circ$
(3)angle of refraction is $53.4^\circ$
(4)refraction is not possibleOfficial answer

Official answer

Option 4

NTA final key.

Chapter: Ray Optics and Optical Instruments
Topic: Refraction and Snell's Law
Idea tested: Total Internal Reflection

Same idea in other shifts

Asked 6× in all

7 Apr 2025, Shift 2 · Q42A transparent block A having refractive index $\mu=1.25$ is surrounded by another medium of refractive index $\mu=1.0$ as shown in figure.…MediumSingle correctHas a figure
8 Apr 2024, Shift 1 · Q43Critical angle of incidence for a pair of optical media is $45^\circ$ . The refractive indices of first and second media are in the ratio:EasySingle correct
11 Apr 2023, Shift 1 · Q35The critical angle for a denser-rarer interface is $45^\circ$ . The speed of light in rarer medium is $3 \times 10^8$ m/s. The speed of…EasySingle correct
8 Jan 2020, Shift 1 · Q15The critical angle of a medium for a specific wavelength, if the medium has relative permittivity 3 and relative permeability…MediumSingle correct
9 Jan 2020, Shift 2 · Q17There is a small source of light at some depth below the surface of water (refractive index $= \frac{4}{3}$ ) in a tank of large cross…HardSingle correct

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.