JEE Main 2021PhysicsWave OpticsMediumNumerical

JEE Main 2021 — Wave Optics Question with Solution

JEE Main 2021 (26 Aug Shift 1)

Question

White light is passed through a double slit and interference is observed on a screen 1.5 m away. The separation between the slits is 0.3 mm. The first violet and red fringes are formed 2.0 mm and 3.5 mm away from the central white fringes. The difference in wavelengths of red and violet light is in nm.

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Show full solutionCorrect answer: 300
Correct answer
300

Step-by-step explanation

y1=λrDd

y2=λvDd

λr−λv=y1−y2dD=(3.5−2)mm×0.3mm1.5m=300nm

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About this question

This is a previous-year question from JEE Main 2021, 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.