Light — Science STD 7 — Question

Isaac Newton was the first person to split sunlight into seven colors using a glass prism.
When he tried to split the band of colors further using a second prism placed in the inverted position as compared to that of the first, he observed that the emergent ray was white colored.
This gave him an idea that sunlight is made up of $7$ colors and any other light that gives a spectrum similar to that of sunlight is often referred to as white light.