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The work function of a substance is 4.0 eV . Then longest wavelength of light that can cause photoelectron emission from this substance approximately

Options

  1. A540 ~nm
  2. B400 ~nm
  3. C310 ~nm
  4. D220 ~nm

Correct answer

C. 310 ~nm

Step-by-step solution

hc = W _ longest = hc W = 6.6 10⁻³⁴ 3 10^8 4.0 1.6 10⁻¹⁹ _ longest 310 ~nm .

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