A photoelectric surface is illuminated successively by monochromatic light of wavelengths λ   a n…

A photoelectric surface is illuminated successively by monochromatic light of wavelengths λ and λ2. If the maximum kinetic energy of the emitted photoelectrons in the second case is 3 times that in the first case, the work function of the surface is :
  1. hc2λ
  2. hcλ
  3. hc3λ
  4. 3hcλ

Solution

K.Eλ=hcλ-ϕ

K.Eλ2=hcλ2-ϕ

K.Eλ2=3K.Eλ

⇒  ϕ=hc2λ

Asked in: JEE Main 2016 (10 Apr Online)

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