how the visible light reflects 7 colours?

first of all the visible light can be refracted to have 7colours.
the seven colours include red, orange, yellow, green, blue, indigo and violet. the arrangement is according to the increasing of frequency and decreasing of wavelength. they can be refracted by a prism to form 7 colours because they have their own refractive index. the higher the refractive index, the higher the refraction. violet refracted the most with lower speed and red refracted the least with higher speed.

The concept should be white light is composite of many light with different wave length(different wave length, different color). You can see many colors of light because white light is under refraction. i.e. refracted through a prism, and the colors are separated.