Question

When a lens refracts different wavelengths at different angles, causing the light in the lens that passes through the edges to be slightly dispersed, this is known as:?

Answer 1

The technical name was kinda given in the question, and I'm guessing that's what they want: Dispersion. It refers to the phenomenon of different frequencies traveling at different speeds through a medium. This is due to the fact that the relative electric permittivity is a complex quantity that is a function of frequency. The relative electric permittivity,
`\epsilon_(r)`, is related to the speed of the wave in the medium by the relation:

`c' = \frac{c}{ \sqrt{ \epsilon_(r) } }`
Since this speed is a function of permittivity, and permittivity is a function of frequency, speed is a function of frequency.
Probably more info than you needed....