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JIPMER2005PhysicsDual Nature of Matter

If work function of a metal is 4.2 eV , the cut off wavelength is

Options

  1. A8000 Å
  2. B7000 Å
  3. C1472 Å
  4. D2950 Å

Correct answer

D. 2950 Å

Step-by-step solution

Suppose the cut off wavelength is represented by ₀ So, h c ₀ = work function =W₀ aligned h c ₀ & =4.2 1.6 10⁻¹⁹ ₀ & = 6.6 10⁻³⁴ 3 10^8 4.2 1.6 10⁻¹⁹ & =2946 10⁻¹⁰ ~m & 2950 Å aligned

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