What is the wavelength and frequency of a rainbow?what it is exactly?

When white light hits the water droplets, it gets refracted into seven different colors: violet, indigo, blue, green, yellow, orange and red. They vary in their wavelengths and also in their frequencies.

Wavelength is the distance between two successive crests or two successive troughs. Red has the longest wavelength while violet has the shortest wavelength.

Frequency is the inverse proportional of wavelength. It is the number of crests or troughs that pass a point per second. So, red would have the shortest frequency while violet has the highest frequency.