JEE Main 2020 · PhysicsMultiple choiceSingle correctEasyCalculation

JEE Main 8 January 2020, Shift 2, Physics Q17

Question 17 of 75 in this shift, Physics question 17 of 25, Section A.

In a double-slit experiment, at a certain point on the screen the path difference between the two interfering waves is

\frac{1}{8}

th of a wavelength. The ratio of the intensity of light at that point to that at the centre of a bright fringe is :

(1) $0.853$ Official answer
(2) $0.760$
(3) $0.672$
(4) $0.568$

Official answer

Option 1

NTA final key (Jan 2020).

Chapter: Wave Optics
Topic: Young's Double Slit
Idea tested: Intensity at Fractional Path Differences

Same idea in other shifts

Asked 6× in all

2 Apr 2026, Shift 2 · Q46In a Young's double slit experiment, the intensity at some point on the screen is found to be $\frac{3}{4}$ times of the maximum of the…MediumNumerical value
6 Apr 2026, Shift 1 · Q36In interference experiment the path difference between two interfering waves at a point $A$ on the screen is $\lambda/3$ , where $\lambda$ …EasySingle correct
6 Apr 2026, Shift 2 · Q45In a Young double slit experiment, the wavelength of incident light is 6000 Å, the separation between slits $S_1$ and $S_2$ is 5 cm and…MediumDiagram basedHas a figure
9 Apr 2024, Shift 1 · Q59In a Young's double slit experiment, the intensity at a point is $\left(\frac{1}{4}\right)^{th}$ of the maximum intensity, the minimum…MediumNumerical value
6 Sep 2020, Shift 2 · Q24A Young's double-slit experiment is performed using monochromatic light of wavelength $\lambda$ . The intensity of light at a point on the…MediumNumerical 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.