Question

what do you understand by dispersion ? who observed it first

Answer 1

Phenomenon of spiliting white light through a glass prism into its seven constituent colour is known as dispersion

Sir isaac newton

Answer 2

In optics, dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency. Media having this common property may be termed dispersive media. Sometimes the term chromatic dispersion is used for specificity. Although the term is used in the field of optics to describe light and other electromagnetic waves, dispersion in the same sense can apply to any sort of wave motion such as acoustic dispersion in the case of sound and seismic waves, in gravity waves (ocean waves), and for telecommunication signals along transmisson lines (such as caoxial cable) or optical fiber.

Isaac Newton in 1666 obsrved it first.


hope it helps.