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JEE Main20203 Sep 2020Morning ShiftPhysicsDual Nature of MatterActual

When the wavelength of radiation falling on a metal is changed from 500 nm to 200 nm , the maximum kinetic energy of the photoelectrons becomes three times larger. The work function of the metal is close to:

Options

  1. A0 . 81 eV
  2. B1 . 02 eV
  3. C0 . 52 eV
  4. D0 . 61 eV

Correct answer

D. 0 . 61 eV

Step-by-step solution

KE m a x = hc λ - ϕ = hc 500 - ϕ .....(i) Now, 3 KE max = hc 200 - ϕ .....(ii) From equation (i) and (ii) ii i = 3 1 = hc 200 - ϕ hc 500 - ϕ Put the value of hc = 1237 . 5 and solving ϕ = 0 . 61 eV

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