Question

How speed of different light colour affect refraction or bending when change in medium for red colour it bend very little and violet colour bend very more when passes through prism so how bending works for different light colour?

Answer 1

Each colour has a different wavelength, and each colour bends differently from other colours. Short wavelengths are slowed more sharply upon entering glass from air than are long wavelengths. Red light has the longest wavelength and is bent the least. Violet light has the shortest wavelength and is bent the most. Thus violet light travels more slowly through glass than does any other color and red light travels fastest.
Why? That’s a little harder. High frequency EM waves (violet light) drive the electrons of the medium back and forth more often and are thus interacting more strongly with it. To analyze this phenomenon further really requires a discussion of maxwell equation which you will learn in higher classes