JEE Main 2021 · PhysicsMultiple choiceSingle correctEasyCalculation

JEE Main 24 February 2021, Shift 1, Physics Q20

Question 20 of 90 in this shift, Physics question 20 of 30, Section A.

In a Young’s double slit experiment, the width of the one of the slit is three times the other slit. The amplitude of the light coming from a slit is proportional to the slit-width. Find the ratio of the maximum to the minimum intensity in the interference pattern.

(1) $4:1$ Official answer
(2) $2:1$
(3) $1:4$
(4) $3:1$

Official answer

Option 1

NTA final key.

Chapter: Wave Optics
Topic: Young's Double Slit
Idea tested: Intensity Ratio from Slit Widths

Same idea in other shifts

Asked 6× in all

3 Apr 2025, Shift 2 · Q41Two monochromatic light beams have intensities in the ratio 1:9. An interference pattern is obtained by these beams. The ratio of the…EasySingle correct
3 Apr 2025, Shift 2 · Q43Width of one of the two slits in a Young's double slit interference experiment is half of the other slit. The ratio of the maximum to the…MediumSingle correct
4 Apr 2024, Shift 2 · Q46The width of one of the two slits in a Young's double slit experiment is 4 times that of the other slit. The ratio of the maximum of the…EasySingle correct
25 Jun 2022, Shift 2 · Q44The interference pattern is obtained with two coherent light sources of intensity ratio 4:1. And the ratio…MediumSingle correct
30 Jun 2022, Shift 1 · Q47Find the ratio of maximum intensity to the minimum intensity in the interference pattern if the widths of the two slits in Young's…EasySingle 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 108 of the 174 JEE Main shifts held from 2017 to 2026.