The work function for a metal surface is 8.28 eV. The threshold wavelength for this metal surface is :
Answer & explanation
Correct answer: option 3
Threshold wavelength of the metal is
$ \lambda = \frac{hc}{\phi} = \frac{6.62\times 10^{-34}\times 3\times 10^8}{8.28\times 1.6\times 10^{-19}}= 1.5\times 10^{-7}m$