This is quite a good question that concerns one of the most important effects of science, the Photoelectric Effect. I do not want to get boring but probabbly you would like to read about it. Again I do not want to be boring but 4C of charge is nothing without a ddp to move it and get Electrical Energy as flow of charges called electricity. Let us say you apply #10V#; this means that each coulomb of charge will carry #10J# of energy. But what do we do with these #10J# of energy? We send them in the filament of our "Light Generator" (a light bulb) so that electrons can use this energy to jump and come back emitting Photons!!! The problem is that the jumps are of different heights (normally) and the photons emitted cover a wide spectrum (red to blue) giving a white light in the mixture.
What is the electricity required to produce 1 photon,red photon and blue photon?