JEE Main 2015PhysicsWave OpticsEasyMCQ

JEE Main 2015 — Wave Optics Question with Solution

JEE Main 2015 (04 Apr)

Question

Assuming that the human pupil has a radius of 0.25 cm and a comfortable viewing distance of 25 cm. The minimum separation between two point objects that the human eye can resolve for the light of wavelength 500 nm is

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Show full solutionCorrect option: C
Correct answer
C30 μm

Step-by-step explanation

By Fraunhofer diffraction through a circular aperture, θ=1.22λd

d= diameter of pupil =2×0.25=0.5 cm
λ=500 nm. The first dark ring is formed by the light diffracted from the hole at an angle θ with the axis. Viewing distance, D=25 cm∴ The minimum separation between 2 objects =Dθ=25×10-2×1.22×500×10-95×10-3 m
Dθ=30×10-6 m⇒Dθ=30 μm.

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About this question

This is a previous-year question from JEE Main 2015, 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.