Question

why do different colours get separated when white light passes through prism​

Answer 1

due to refraction in the glass prism the white light separated into seven colours that is it bends towards the normal and get separated into seven colours
hope it help

Answer 2

white light contain 7 colour vibgour every colour have different frequency and wavelength when white light retract on the surface it deviate due to refraction the light of different colour will deviate in different frequencies so it's seven different colour appear which is visible in our eye.