Physics

Problem

Light of wavelength

400\,\text{nm}

falls on a certain metal surface and the emitted photoelectrons are stopped by a potential of

0.8\,\text{V}

. When the incident wavelength is changed to

450\,\text{nm}

, no photoelectric emission is observed. (Take

h = 6.63\times10^{-34}\,\text{J s}

c = 3.0\times10^{8}\,\text{m s}^{-1}

and

e = 1.6\times10^{-19}\,\text{C}

) a. Part 1: Calculate the work function of the metal (in eV). b. Part 2: Determine the threshold frequency of the metal.