Question

Name the seven prominent colours of the white light spectrum in order of their frequencies
A. Violet, Indigo, Blue, Green, Yellow, Orange, Red
B. Red, Orange, Yellow, Green, Blue, Indigo, Violet
C. Red, Orange, Violet, Yellow, Green, Blue, Indigo
D. Orange, Yellow, Green, Red, Blue, Indigo, Violet

Answer 1

Hint: White light spectrum or the visible light spectrum is the part of the EM spectrum that is visible by the naked human eye. And white light is nothing but a collection of all the lights of the visible light in equal intensities. As all EM rays, light is also characterised by its wavelength and frequency. Light in order of their wavelengths is remembered by the acronym VIBGYOR.

Complete answer:
Light is an electro-magnetic radiation, and thus as all EMR it also lies on the Electromagnetic Spectrum. The electromagnetic spectrum is the collective term for all possible frequencies of electromagnetic radiation. The frequencies used in EMR spectrum all possible values, of all the EMR found in practical application Radio waves is found at the lowest end of the spectrum and thus has the lowest frequency and Gamma Radiation is the name given to the waves having highest frequencies.
The visible portion of the Spectrum has frequencies from 400–790 terahertz and are detectable by the naked human eye. As the frequency varies the colour of the light perceived also varies. The visible light spectrum is also called the white light spectrum as white light is nothing but a collection of all the lights of the visible light in equal intensity. The visible spectrum or the white light spectrum can be divided into seven prominent colours namely, Violet, Indigo, Blue, Green, Yellow, Orange and Red. These lights are often listed in the order given since it is in the order of their wavelengths. And since we know that the frequency is inversely proportional to the wavelength. The seven prominent colours of the white light spectrum in order of their frequencies would be; Red, Orange, Yellow, Green, Blue, Indigo, Violet

So, the correct answer is “Option B”.

Note:
It is important to remember the white light spectrum as well as their orders of intensities. The order of wavelengths determines the order of the angle by which the light of the spectrum would deviate when passed through a prism. An acronym is used for the remembering purpose, that acronym is VIBGYOR and thus the order of light in order of their wavelengths will be Violet, Indigo, Blue, Green, Yellow, Orange, Red.