Work function of a photosensitive material is 4.0 eV. Longest wavelength causing photoemission is approximately:
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Work function of a photosensitive material is 4.0 eV. Longest wavelength causing photoemission is approximately:

G1 Physics · Accepted Answer

Threshold wavelength λ₀ = hc/W = (1240 eV·nm)/(4.0 eV) = 310 nm. Answer: D.