Alight wave travels at 3.0 x 10^8 m/s. if the wavelength of a red wave is 700 x 10^-9m, what is the frequency?

Frequency  =  (speed) divided by (wavelength)

                 = (3 x 10⁸ m/s)  /  (700 x 10⁻⁹ m)

                 =  (3 / 700) x 10¹⁷ ( per sec )

                 =    4.286 x 10¹⁴  per sec  =  4.286 x 10¹⁴ Hz.

                                                           =      42,860 GHz .