hertz was able to calculate the velocity of the waves by reflecting radio waves off a metal sheet and measuring the wavelength of the standing wave set up by interference. substituting this wavelength and the known frequency of the wave generator into the general wave equation, v(or c) = lambda x f, hertz calculated the wave speed at 3 x 108 ms^-1, very close to the values for the speed of light earlier estimated by maxwell and measured by fizeau. thus he deduced that light is a transverse electromagnetic wave.