Theory of Light: Any theory regarding propagation of light must explain the properties of light. Since, light is a form of energy, it is transferred from one place to another. Light does not require a material medium for its propagation.
In general, there are two possible modes of propagation of energy from one place to another
(i) by stream of material particles moving with a finite velocity
(ii) by wave motion, wherein the matter through which the wave propagates does not move along the direction of the wave.