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Question: Answered & Verified by Expert

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)

ChemistryStructure of AtomJEE MainJEE Main 2019 (08 Apr Shift 2)
Options:
  • A 49λ
  • B 34λ
  • C 23λ
  • D 12λ
Solution:
2645 Upvotes Verified Answer
The correct answer is: 49λ

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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