What does it mean, when it says "for visible light (ROYGBIV) which has the shortest wavelength? which has the longest? place all other colors in order based on their wavelength from shortest to longest.

Answer 1

Red has the longest wavelength, while violet has the shortest.
Arranging the colors from shortest to longest wavelength: VIBGYOR

Answer 2

So does VIBGYOR mean Violet, Indigo, Blue, Green, Yellow, Orange and Red?

Answer 3

Yes.