how many does the rainbow has

very interesting you discussion, i think has 5 colors.

I have always been taught to remember the name Roy G. Biv, which stands for Red, orange, yellow, green, blue, indigo, and violet!

The mnemonic I have always used is "Richard of York Gained Battles In Vain". I suppose that that was memorable and meaningful to students of English History but, these days, it's just a sentence one remembers for the initial letters which also stand for: Red, Orange, Yellow, Green, Blue, Indigo, Violet. Since the visible spectrum is continuous, the rainbow technically has an infinite number of colours, but these are the seven colours which are most easy to distinguish. The human eye is sensitive to three main colours: Red, Yellow and Blue (called the Primary colours) and all of the other colours are perceived as a mixture in various percentages of these three. Mixtures of just two of these three colours in equal proportions are called Secondary colours and these are: Red + Blue = Violet or Purple; Red + Yellow = Orange and Blue + Yellow = Green. Indigo is a deep blue, intermediate between Blue and Violet.

Rainbow has 7 colours, It is known as VIBGYOR. From, these colours we can create 262 million colours by mixing only 7 colours. VIBGYOR means V-Violet I-Indigo B-Blue G-Green Y-Yellow O-Orange R-Red

remember this ROYGVIB, I hope i am not mistaken or still remember it that way, R-red ; O - orange; Y-yellow; G-green; V-violet; I-indigo; B-blue, i just don't remember which comes first the blue or the indigo. And so it is seven,let us just wait for the opinion of others.