Newton directed a narrow beam of white (sunlight) light onto a glass prism, resulting in a colored band (color spectrum) on the screen behind the prism, because after refraction in the prism, the beam split into all the colors of the rainbow. From experience it follows that white light is a composite, a mixture of all the colors of the rainbow.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.