Question

Why does white light split up into different colours while passing through a glass prism?

Answer 1

HELLO THERE!

A polychromatic ray of light (light consisting of many rays of different wavelengths), when passed through a prism, disperses (splits) into its constituent colours.

WHY?

Speeds of lights of all wavelengths are same in air. However they are not same in a glass prism. When the ray of light is passed through a glass prism, they slow down to different extents (the light having least wavelength deviates the most, and the light having greatest wavelength deviates the least).

So, dispersion occurs, and the light splits up.

Example: White light consists of the seven colours, Violet, Indigo, Blue, Green, Yellow, Orange and Red. When it is passed through the prism, Red light having the greatest wavelength, deviates the least, and then follows Orange, then Yello, then Green, and finally, Violet deviates the most. Hence the lights split up, and dispersion takes place.

HOPE MY ANSWER IS SATISFACTORY...

Thanks!

Answer 2

We know that light is composed of even colors whose mnemonics is $\bf{VIBGYOR}$.

Actually, prism is made up of glass whose inner density is differnt from the surrounding Air density.

So, thier chnage in medium causes refraction of light and hence, splittion.