The electromagnetic wave derivation uses the fact that charge enclosed is zero and it goes to obey plane wave equations. Lets say we were deriving a wave equation from maxwell's equations for electron wave motion, but we assume that charge enclosed is not zero, and come up with some differential equation not like the standard wave equation. Using this if we were to find the wavelength, and lets say that wavelength is 95% of the de-broglie wavelength, then would it not be more better to use this new wave equation, rather than photon equation which assumes charge is zero. One can say that matter wave has nothing to do with charge, but whenever its derivation is done, its assumed as plane wave, which is obeyed by charge less particle like photon. If there is another, lets say Quack-wave, which is derived taking charge enclosed as e and J≠o, what would be the basis for rejecting quack- wave over plane wave. Note: Assume that the wavelength using quack-wave is independent of the charge itself, therefore will work for neutral atoms also, just assume that quack wave equation gives a different constant C which gives us the matter wave as C * de-broglie wavelength.