why rainbow have red orange yellow green blue dark blue purple
Answers
The colors of the rainbow represent seven major sections of the light spectrum. You could pick any section of them. You could use red-orange and other tertiary colors instead of the standards, but the light spectrum never changes.
Explanation:
ROYGBIV or Roy G. Biv is an acronym for the sequence of hues commonly described as making up a rainbow: red, orange, yellow, green, blue, indigo and violet. The initialism is sometimes referred to in reverse order, as VIBGYOR.In Classical Antiquity, Aristotle claimed there was a scale of seven basic colors.[1] In the Renaissance, several artists tried to establish a new sequence of up to seven primary colors from which all other colors could be mixed. In line with this artistic tradition, Newton divided his color circle, which he constructed to explain additive color mixing, into seven colors.[2] His color sequence including the tertiary color indigo is kept alive today by the Roy G. Biv mnemonic. Originally he used only five colors, but later he added orange and indigo to match the number of musical notes in the major scale.[3][4]
The Munsell color system, the first formal color notation system (1905), names only five "principal hues": red, yellow, green, blue, and purple.