The surface of a metal is illuminated with light of 400 nm. The kinetic energy of the ejected photoelectrons was found to be 1.68 eV. The work function of the metal is: (hc = 1240 eV.nm)?
1.41 eV
1.68 eV
3.09 eV
1.51 eV
Solution:
From the photoelectric equation, hc/λ = φ + (KE)max 1240/400 = φ + 1.68 ⇒ φ = 1.41 eV