The binding energy of electrons in a metal is 193 kJ$mo{l}^{-1}$.The threshold frequency of the metal is 

Binding energy of electron per atom of the metal

            $\begin{array}{l}{E}_{bind}=\frac{193\times {10}^{3}Jmo{l}^{-1}}{6.022\times {10}^{23}mo{l}^{-1}}=3.20\times {10}^{-19}J\\ v=\frac{E_{bind}}{h}=\frac{3.20\times {10}^{-19}}{6.626\times {10}^{-34}}=4.83\times {10}^{14}{s}^{-1}\end{array}$