What is the frequency of a photon of blue light whose wavelength is 4.5 m.

Your question is not clear but if you can explain yourself i would be glad to .  just trying to : ))

The main types of electromagnetic radiation. radio  waves have  the lowest frequencies  and  longest  wavelengths, while gamma  waves have highest frequencies  and shortest wavelengths. the wavelengths vary across the electromagnetic spectrum from about 10–15 m to more than 104 m.hope it !