Light of wavelength 500 nm illuminates a metal of work function 2.28 eV. De Broglie wavelength of emitted electron is:
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Light of wavelength 500 nm illuminates a metal of work function 2.28 eV. De Broglie wavelength of emitted electron is:

G1 Physics · Accepted Answer

Photon energy ≈ 1240/500 = 2.48 eV. Maximum electron kinetic energy ≈ 2.48 − 2.28 = 0.20 eV. λ = 12.27/√0.20 Å ≈ 27.4 Å = 2.74 × 10⁻⁹ m for the most energetic photoelectrons. Slower electrons have larger wavelengths; the source key C takes approximately 2.8 × 10⁻⁹ m as minimum. Answer: C.