The work function of a substance is 3 . 0 eV . The longest wavelength of light that can cause the emission of photoelectrons from this substance is approximately:

Question

The work function of a substance is 3 . 0 eV . The longest wavelength of light that can cause the emission of photoelectrons from this substance is approximately:, 215 nm, 414 nm, 400 nm, 200 nm

MARKS App · Accepted Answer

For longest wavelength, the emitted electron will have nearly zero kinetic energy. Therefore, λ = h c W e ⇒ λ = 1240 nm - eV 3 eV ⇒ λ = 413 . 33 nm ⇒ λ max ≈ 414 nm

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