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Saturday, 31 October

JEE Main 2026 · PhysicsNumerical answerNumerical valueMediumCalculation

JEE Main 4 April 2026, Shift 2, Physics Q50

Question 50 of 75 in this shift, Physics question 25 of 25, Section B.

In a double slit experiment, when one of the slits is covered by a transparent mica sheet of refractive index 1.56, the central fringe shifts to the position of 7th7^{\text{th}} bright fringe, obtained with both slits uncovered. If the light source wavelength is 450 nm, the thickness of mica sheet is α×10−9\alpha\times10^{-9} m. The value of α\alpha is ________.

Official answer

5625

NTA final key.

Chapter
Wave Optics
Topic
Young's Double Slit
Idea tested
Fringe Shift by Thin Slab

Same idea in other shifts

Asked 3× in all
  1. 9 Apr 2024, Shift 2 · Q52Monochromatic light of wavelength 500500 nm is used in Young's double slit experiment. An interference pattern is obtained on a screen.…MediumNumerical value
  2. 28 Jun 2022, Shift 2 · Q46In young’s double slit experiment performed using a monochromatic light of wavelength λ\lambda, when a glass plate (μ\mu=1.5) of…MediumSingle 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.