What are the ways (both natural and artificial) in which em radiation is generated? Here is one of the methods: We take a point charge (or more practically a charged sphere with uniform charge distribution) such that we can voluntarily fluctuate the amount of charge on it. We fluctuate the charge of the particle sinusoidally and hence fluctuate the electromagnetic field associated with it. We have by definition an electromagnetic wave. Let us discuss some more ways. I would like to know all the natural ways and also the artificial techniques. In particular, can somebody explain to me how actually is an em wave generated when an electron in an atom, falls from a higher energy state to a lower one? I mean, alright I understand that the electron, when it falls back, loses energy in the form of em wave, but what is the mechanism of its generation?