JEE Main 2020 — Wave Optics Question with Solution
From: JEE Main 2020 (Online) 9th January Evening Slot
Question
In a Young's double slit experiment 15 fringes
are observed on a small portion of the screen
when light of wavelength 500 nm is used. Ten
fringes are observed on the same section of
the screen when another light source of
wavelength is used. Then the value of is
(in nm) __________.
Enter your answer
Show full solutionCorrect answer: 750
Correct answer
750
Step-by-step explanation
The length of the screen used portion for 15
fringes, and also for ten fringes
15 500 = 10
15 × 50 =
= 750 nm
15 500 = 10
15 × 50 =
= 750 nm
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This is a previous-year question from JEE Main 2020, covering the Wave Optics chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.