JEE Main 2019ChemistryStructure of AtomMediumMCQ

JEE Main 2019Structure of Atom Question with Solution

JEE Main 2019 (08 Apr Shift 2)

Question

If p is the momentum of the fastest electron ejected from a metal surface after the irradiation of light having wavelength λ, then for 1.5 p momentum of the photoelectron, the wavelength of the light should be:

(Assume kinetic energy of ejected photoelectron to be very high in comparison to work function)

Choose an option

Show full solutionCorrect option: A
Correct answer
A49λ

Step-by-step explanation

hν-ϕ=KE

hcλincident=KE+ϕ

Given ϕ<<KE

hcλincidentKE

hcλincident=p22m ......(i)

hcλ'=1.5p22m …….(ii)

Divide (i) and (ii)

λ'λ=p22.25p2

λ'=λ×1002.25=49

λ'=49λ

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About this question

This is a previous-year question from JEE Main 2019, covering the Structure of Atom chapter of Chemistry. 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.