Physics

Problem

Ultraviolet light of wavelength

200\,\text{nm}

is incident on a metal whose threshold frequency is

5.0\times10^{14}\,\text{Hz}

. Calculate the maximum kinetic energy released per mole of emitted electrons.

(h = 6.63\times10^{-34}\,\text{J s};\; c = 3.0\times10^{8}\,\text{m s}^{-1};\; N_{\!A}=6.02\times10^{23}\,\text{mol}^{-1})

6.0\times10^{5}\,\text{J mol}^{-1}

4.0\times10^{5}\,\text{J mol}^{-1}

1.2\times10^{5}\,\text{J mol}^{-1}

2.5\times10^{5}\,\text{J mol}^{-1}