JEE Main 2021 · PhysicsMultiple choiceSingle correctEasyConceptual

JEE Main 27 August 2021, Shift 2, Physics Q18

Question 18 of 90 in this shift, Physics question 18 of 30, Section A.

The light waves from two coherent sources have same intensity

I_1=I_2=I_0

. In interference pattern the intensity of light at minima is zero. What will be the intensity of light at maxima ?

(1) $2\ I_0$
(2) $5\ I_0$
(3) $4\ I_0$ Official answer
(4) $I_0$

Official answer

Option 3

NTA final key.

Chapter: Wave Optics
Topic: Young's Double Slit
Idea tested: Resultant Intensity Formula

Same idea in other shifts

Asked 13× in all

3 Apr 2025, Shift 1 · Q50Two coherent monochromatic light beams of intensities 4I and 9I are superimposed. The difference between the maximum and minimum…EasyNumerical value
7 Apr 2025, Shift 1 · Q41Two plane polarized light waves combine at a certain point whose electric field components are $E_1 = E_0 \sin\omega t$ …EasySingle correct
6 Apr 2024, Shift 2 · Q54Two coherent monochromatic light beams of intensities $I$ and $4I$ are superimposed. The difference between maximum and minimum possible…EasyNumerical value
1 Feb 2024, Shift 2 · Q59In Young's double slit experiment, monochromatic light of wavelength 5000 Å is used. The slits are 1.0 mm apart and screen is placed at…MediumNumerical value
31 Jan 2024, Shift 1 · Q59Two waves of intensity ratio 1:9 cross each other at a point. The resultant intensities at that point, when (a) Waves are incoherent is…MediumNumerical value
10 Apr 2023, Shift 2 · Q47The ratio of intensities at two points P and Q on the screen in a Young's double slit experiment where phase difference between two waves…EasySingle correct
13 Apr 2023, Shift 2 · Q46In a Young's double slits experiment, the ratio of amplitude of light coming from slits is 2:1. The ratio of the maximum to minimum…EasySingle correct
27 Jul 2022, Shift 1 · Q53Two beams of light having intensities I and 4I interfere to produce a fringe pattern on a screen. The phase difference between the two…EasyNumerical value

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.