[tex]dane:\\\lambda = 6\cdot10^{-10} \ m\\v = c = 3\cdot10^{8}\frac{m}{s}\\szukane:\\f = ?\\\\v = \frac{\lambda}{T}\\\\ale \ \ T = \frac{1}{f}, \ zatem:\\\\v = \lambda\cdot f \ \ /:\lambda\\\\f = \frac{v}{\lambda}\\\\f = \frac{3\cdot10^{8}\frac{m}{s}}{6\cdot10^{-10} \ m} = 0,5\cdot10^{18} \ Hz = 5\cdot10^{17} \ Hz[/tex]