Quantum (Photon) Theory of Dispersion

When white light beam falls on a prism, the emergent light consists of different colors. According to Wave Theory, the separation of different colors present in white light is because of different deviations suffered by them, when they pass through a prism. The wavelength of different colors is different. Red color has maximum wavelength and violet color has minimum wavelength i.e. λ_ris greater than λ_v. Therefore, Refractive index for red color is less than that of violet color, as per Cauchy’s formula. So the speed of red color is more than violet in denser medium. But this is not true; the speed of all colors remains same (c) inside the crystal. When light enters the denser medium, the photons are being absorbed & emitted continuously. The speed of photon between two consecutive absorption or emission is 3 × ?10?^8 m/s , but due to difference in number of absorption and emission of various colors (photons) by atoms, they spent different times inside the crystal. According to this Quantum theory, massive photon suffers more absorption and emission. Due to this they spent more time inside the transparent medium and also deviates more. In every absorption and emission process, they suffer unit deviation. Therefore violet deviates more than red photon.