How is refraction related to dispersion?
1 Answer
You first think at refraction; a beam of light passes from a medium to another and get deflected. To distinguish these two media you use the index of refraction
But, the index of refraction
Now we get to dispersion!
A beam of white light passes from a medium to another BUT this beam is the composition of many chromatic components (colours each one at a certain wavelength) and each one has its "personal" index of refraction in the second medium!!!! So each component is deflected of a different amount (have a look at Snell's Law to "see" this deflection).
So basically light of different wavelength is bent of different amounts .
It is a little bit like to have a running competition with a bunch of runners grouped together. They reach a bend and after it they start to run on sand; each runner has a different "reaction" to the new surface (some run faster or slower depending on their velocity on the new surface) and after a while they "disperse" and are not grouped together anymore!!!
Hope it helps!