1. The problem statement, all variables and given/known data We learn from school that when we shine white light through a prism, dispersion occurs. This is because the light of varying wavelengths are refracted to a different extent due to how refractive index varies with the wavelength of light. So why does refractive index vary with wavelength? 2. Relevant equations E = hf? 3. The attempt at a solution Light of varying wavelengths have different amounts of energy. As such it is logical that they would travel at different speeds in a particular medium and be refracted to a different extent. However, it is not a very technical explanation and isn't entirely coherent. I read something about it in a textbook. However, I didn't quite understand ti. Is there any simple explanation for this phenomena?