Is White light a superposition(Interference) of different wavelengths(V,I,B,G,Y,O,R) ? Or is it a mixture of these wavelengths, i do not even properly know about mixtures but my sir told me that for mixture you do not need sources of these light(V,I,B,G,Y,O,R) to be COHERENT , so we can light up different bulbs(each with different color) and the resultant we would get is white light,but how is mixture possible(scientific explanation) I mean what are the waves doing when we say ther are just mixing up ???Why is there no need of coherency conditions since eventually these are waves and there must be superposition???