As light enters a raindrop it is refracted. The index of refraction of water is slightly different for different colors (frequencies) of light, this is know as [i]dispersion[/i]. As a result of dispersion different colors of light travel different paths within the raindrop and emerge (after reflecting off the back) traveling in different directions. The incoming light has been separated into its constituent colors.

By moving the sliders you may change the index of refration of the red light and the violet light. [br][br][list][br][*]Move the sliders so that the index of refraction is the same for both colors (i.e. no dispersion). Are the colors separated?[br][*]The index of refraction for red light in water is [math]n_r=1.330[/math] and the index of refraction for violet light in water is [math]n_v=1.343[/math][br]Set the sliders to these values. The deviation angle is the angle between the incoming light direction and the outgoing direction.[br]Which color has the largest deviation angle?[br][/list]