Physics · Einstein's photoelectric equation, particle nature of light

Threshold wavelength of tungsten is 2300 angstrom. If ultraviolet light of wavel

Threshold wavelength of tungsten is 2300 angstrom. If ultraviolet light of wavelength 1800 angstrom is incident on it, then the maximum kinetic energy of photoelectrons would be?

  • A. 1.5 ev
  • B. 2.5ev
  • C. 3.0 ev
  • D. \( 5.0 \mathrm{eV} \)

Step-by-step solution

Using the photoelectric equation: KEmax = hc(1/λ - 1/λ₀). With hc = 12400 eV·Å, λ = 1800 Å, λ₀ = 2300 Å, KEmax = 12400 × (1/1800 - 1/2300) = 12400 × (500/4140000) ≈ 1.5 eV.
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