What is the nature of white light? Why does red or blue paper appear red or blue? What colors of visible light does a black object reflect and absorb?

White light consists of all the frequencies of
electromagnetic radiation that are visible to us. In other words, white light is made up
of all the colors of light. Objects that appear white do not absorb light of any color.
Light of any color that falls on them is reflected back.

An
object that has any other color absorbs light of all colors except its own color. For
example a red object absorbs light of all colors except red; similarly, a blue object
reflects only blue light, all the other colors are absorbed by
it.

A black object appears black because it absorbs light
of all colors that fall on it. Light of none of the colors falling on an ideal black
object is reflected back by it.