Which color is most bent and which color is least bent? Why?

Answer 1

Light enters the prism and is refracted by the glass. The violet is bent more than the yellow and red, so the colors separate.

bent most: violet
bent least: red
because: violet has higher frequency/shorter wavelength

Answer 2

The amount that light is bent or refracted as it passes through a prism is determined by the index of refraction of the material. If the index of refraction were constant for all colors, or wavelengths, they would all be bent by the same amount.

Virtually all materials have what is called "dispersion" in the refractive index, where the refractive index changes with wavelength. The dispersion is caused by the presence of absorption bands in the material. For example, glass absorbs light at both infrared and violet wavelengths. As you go from the infrared into the visible spectrum the refractive index first increases rapidly, then the rate of increase slows to almost constant change with wavelength. Once you get into the blue, the refractive index begins to increase more rapidly again as you approach the ultraviolet absorption.

Based on the above discussion blue light (and in general shorter wavelength light) is refracted, or bent, more strongly than red (or longer wavelength) light.

This dispersion in the refactive index is used in the design of prisms to disperse, or separate light into its different colors. Without dispersion, prisms would not work.

Dispersion is a problem for lens designers. Dispersion causes the focus of a lens system to be different for different colors. This affects the sharpness of the image and can cause color bands that appear along edges in a photograph. "Achromat" lenses are designed, usually using two different optical materials, to reduce the effect of dispersion.

Answer 3

Hi. Refraction is stronger is longer wavelengths, I think, due to the influence of the medium it is entering at an angle. (Only at an angle.)