JEE Main 2017PhysicsDual Nature of MatterHardMCQ

JEE Main 2017 — Dual Nature of Matter Question with Solution

JEE Main 2017 (08 Apr Online)

Question

The maximum velocity of the photoelectrons emitted from the surface is v when light of frequency n falls on a metal surface. If the incident frequency is increased to 3n, the maximum velocity of the ejected photoelectrons will be:

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Show full solutionCorrect option: A
Correct answer
Amore than 3v

Step-by-step explanation

According to Einstein's photoelectric effect, 

KEmax=hcλ-ϕ

The incident energy of the photon is E1=12mv2=hn-ϕ  ...1

If incident frequency increased to 3n

E2=12mv22=3hn- ϕ

=3hn-ϕ+2ϕ 

E2=3 E1+2ϕ

⇒12mv22=32mv2+2ϕ

⇒v22=3v2+4ϕm

⇒v2>v3

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About this question

This is a previous-year question from JEE Main 2017, 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.