Questions & Answers

Which color of the light has the longest wavelength?
A. Red
B. Blue
C. Green
D. Violet

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Hint: First we need to know the values of wavelength or frequency for different colors of light or different types of rays, then we can easily compare among them to know which of the following has the shortest wavelength.

Complete step-by-step answer:
The colour Red has the longest wavelength and violet has the shortest wavelength in the visible spectrum.
VIBGYOR- is the name given to the colours of the rainbow and they are in ascending order of their wavelength they are as follows,
Violet < Indigo < Blue < Green < Yellow < Orange < Red.
We know that Frequency is inversely proportional to wavelength, so Red light rays have the lowest frequency and highest wavelength value. This means that Red light rays have the least number of waves in a second than any other radiation.
Hence option A is the correct option.

Additional Information:
The segment of the electromagnetic spectrum that is visible for the human eye is known as visible light spectrum. We can simply say that this range of wavelength is called visible light. Naturally, the human eye can detect wavelengths from 380 to 700 nanometers.
Wavelength or frequency is a measure of light (unit of wavelength is nanometers) (wavelength of frequency is Hertz). One wavelength is the distance between two successive wave crests or troughs. Frequency (Hertz) is equal to the number of waves that passes a point per second.

Note: Try to remember both the values of wavelength and frequency as it will also help to solve sums related to wavelength and frequency. Frequency is inversely proportional to wavelength so knowing any one of the values between wavelength or frequency will work.