The frequency is 7.18 × 10^14 Hz, c= 3 × 10^8 m/s, where c is the speed of light. But; c = λf, where λ is the wavelength of the wave and f is the frequency. Making λ the subject, we get; λ = c/f = (3 ×10^8)/ (7.18 ×10^14) = 4.17827 × 10^-7 m but 1 m = 10^9 nm Therefore; = (4.17827 ×10^-7) × 10^9 = 417.827 nm Hence, the wavelength= 417.827 nm
