text: microwave region of the spectrum, with a typical wavelength of 3.19 cm. whats the frequency of this in mhz? police “radar guns” (unlike large radar “radio detection and ranging” devices on ships…) utilize electromagnetic radiation signals in the microwave region of the spectrum, with a typical wavelength of 3.19 cm. whats the frequency of this signal in mhz, and the energy per photon in j/photon? frequency has an inverse relationship to the concept of wavelength. the frequency f is equal to the speed c of the wave divided by the wavelength λ (lambda) of the wave: f= c/ λ= 3 10^8/3.19 10^-2 = 9404 mhz