Photoelectric effect: Light of wavelength 400 nm falls on a metal surface having a work function 1.70 eV. What is the maximum kinetic energy of the photoelectrons emitted from the metal? (c = 3.00 × 10⁸ m/s, h = 6.626 × 10^-34 J ∙ s = 4.141 × 10^-15 ev ∙ s, 1 eV = 1.60 × 10^-19 J)

Question

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The energy of the incident photons is calculated using E = hc/λ. Converting 400 nm to meters gives 400 × 10^-9 m. Substituting the values, E = (4.141 × 10^-15 eV ∙ s)(3.00 × 10^8 m/s) / (400 × 10^-9 m) = 3.11 eV. The maximum kinetic energy of the photoelectrons is the photon energy minus the work function: 3.11 eV - 1.70 eV = 1.41 eV.

Photoelectric Effect: Light of Wavelength 400 Nm Falls on a Metal