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The radiation corresponding to 3 → 2 transition of hydrogen atom falls on a metal surface to produce photoelectrons. These electrons are made to enter a magnetic field of 3 × 1 0 - 4 T . If the radius of the largest circular path followed by these electrons is 10.0 mm, the work function of the metal is close to :

Options

  1. A1.8 eV
  2. B1.1 eV
  3. C0.8 eV
  4. D1.6 eV

Correct answer

B. 1.1 eV

Step-by-step solution

We know that R = m υ Bq ∴ υ = Bqr m ∴ KE = 1 2 m v 2 = B 2 q 2 R 2 2m = 0.79 eV Now from photoelectric equation E = ϕ + KE ∴ ϕ = E - KE = 1.89 - 0.79 = 1.1 eV

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