Answer: "The index of refraction of any material (besides vacuum) varies slightly with the frequency of light: the higher the frequency, the greater the index of refraction. Since red light has a lower frequency than violet, its index of refraction will be lower.
If an equation is dimensionally correct, it does not mean that the equation must be true. On the other hand, when the equation is dimensionally correct, the equation cannot be true. Dimensional analysis is a technique used to check whether a relationship is correct
