[tex]Dane:\\\lambda = 2\cdot10^{-7} \ m\\E_{k} = 1,82 \ eV = 1,82\cdot1,6\cdot10^{-19} \ J = 2,9\cdot10^{-19} \ J\\h = 6,63\cdot10^{-34} \ Js \ - \ stala \ Plancka\\c = 3\cdot10^{8} \ \frac{m}{s}\\Szukane:\\W = ?\\\\Rozwiazanie\\\\E_{k} = E_{f}-W\\\\\underline{W = E_{f} - E_{k}}\\\\E_{f} = h\cdot\fracPc}{\lambda}\\\\E_{f} = 6,63\cdot10^{-34} \ Js\cdot\frac{3\cdot10^{8}\frac{m}{s}}{2\cdot10^{-7} \ m}=9,9\csot10^{-19} \ J\\\\\\W = 9,9\cdot10^{-19} \ J -2,9\cdot10^{-19} \ J\\\\\boxed{W = 7\cdot10^{-19} \ J}[/tex]
Odp. Praca wyjścia dla tego metalu W = 7 · 10⁻¹⁹ J.