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The surface of the metal is illuminated with the light of 400 nm . The kinetic energy of the ejected photoelectrons was found to be 1 . 68 eV , the work function of the metal is

Options

  1. A1 . 51   eV
  2. B1 . 42   eV
  3. C3 . 0   eV
  4. D1 . 68   eV

Correct answer

B. 1 . 42   eV

Step-by-step solution

As we know ϕ 0 = h c λ - E k (Einstein's equation) =         ϕ 0 = 1240   eV   nm 400   nm - 1 .68   eV =      3 .1 - 1 .68 = 1 .42   eV

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