JEE Main 2017 — Wave Optics Question with Solution
From: JEE Main 2017 (Online) 8th April Morning Slot
Question
A single slit of width b is illuminated by a coherent monochromatic light of wavelength . If the second and fourthminima in the diffraction pattern at a distance 1 m from the slit are at 3 cm and 6 cm respectively from the central maximum, what is the width of the central maximum ? (i.e. distance between first minimum on either side of the central maximum)
Choose an option
Show full solutionCorrect option: B
Correct answer
B3.0 cm
Step-by-step explanation
For single slit diffraction, sin =
From central maxima the position of nth minima =
Now when,
n = 2, then x2 = = 0.03 . . . .(1)
n = 4, then x4 = = 0.06 . . . .(2)
Performing (2) (1) we get,
x4 x2 = = 0.03
=
As, width of crntral maximum
=
= 2
= 0.03 m
= 3 cm
From central maxima the position of nth minima =
Now when,
n = 2, then x2 = = 0.03 . . . .(1)
n = 4, then x4 = = 0.06 . . . .(2)
Performing (2) (1) we get,
x4 x2 = = 0.03
=
As, width of crntral maximum
=
= 2
= 0.03 m
= 3 cm
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