When a beam of white light passes through a prism, it undergoes dispersion, splitting into its constituent colours (spectrum: Violet, Indigo, Blue, Green, Yellow, Orange, Red - VIBGYOR). This happens because the refractive index of the prism material is different for different wavelengths (colours) of light. Refraction is the bending of light as it passes from one medium to another. The amount of bending depends on the refractive index of the medium and the angle of incidence. For visible light passing through a prism, the refractive index of the prism material is higher for shorter wavelengths and lower for longer wavelengths. Violet light has the shortest wavelength among the colours in the visible spectrum. Red light has the longest wavelength among the colours in the visible spectrum. Since the refractive index is highest for violet light, it is bent the most (deviated the maximum) when passing through the prism. Conversely, since the refractive index is lowest for red light, it is bent the least (deviated the minimum).The order of deviation from maximum to minimum is typically Violet > Indigo > Blue > Green > Yellow > Orange > Red.