The surface of a metal is illuminated with the light of 400 nm

• Matter & Atoms

The surface of a metal is illuminated with the 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. 1.41 eV
2. 1.51 eV
3. 1.68 eV
4. 3.09 eV

Answer

hc/λ = φ + (K.E.)_max

1240/400 = φ + 1.68

φ = 1.41 eV

The correct option is A.