JEE Main 2022PhysicsDual Nature of MatterEasyNumerical

JEE Main 2022 — Dual Nature of Matter Question with Solution

JEE Main 2022 (26 Jun Shift 2)

Question

The stopping potential for photoelectrons emitted from a surface illuminated by light of wavelength 6630Å is 0.42 V. If the threshold frequency is x×1013 s, where x is (nearest integer): (Given, speed light =3×108 m s-1.  Planck's constant =6.63×10-34 J s)

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Show full solutionCorrect answer: 35
Correct answer
35

Step-by-step explanation

We know that, KEmax=hf-ϕ=hcλ-ϕ

Or, hcλ-ϕ=eV0, where, ϕ=hνth and V0 is stopping potential.

So, threshold frequency is 

νth=cλ-eV0h

=3×10866330×10-10-1.6×10-19×0.426.63×10-34

=36.630×1015-1.6×0.426.63×1015

=101536.630-1.6×0.426.63=0.4524-0.1013

νth=35.11×1013

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About this question

This is a previous-year question from JEE Main 2022, covering the Dual Nature of Matter 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.