In the visible spectrum which color has the shortest wavelength

Answer

Hint:When white light enters into a refracting surface it gets scattered into seven different colours. The combination of these colours is called a spectrum. According to Rayleigh’s Law of scattering, the extent of scattering of a light is inversely proportional to its wavelength.

Complete answer:
Electromagnetic waves are those in which there is a sinusoidal variation of electric field vector $(\vec E)$ and magnetic field vector $(\vec B)$ in a direction perpendicular to the direction of propagation of the wave.

The electromagnetic waves exist in an enormous range of frequencies, the systematic distribution of electromagnetic waves in increasing or decreasing order of their frequency or wavelength is called the electromagnetic spectrum. The waves of frequency $4 \times {10^{14}}$ to $8 \times {10^{14}}$ are called visible rays or simply light. It can be seen by humans and other living beings. Its wavelength lies between $700nm$ and $400nm$.

When the visible light passes through a medium of a high refractive index it gets deflected from its path. The extent of deflection depends on the size of the particles of the medium. This phenomenon is called the scattering of light. Smaller particles scatter light of smaller wavelengths while larger particles scatter light of longer wavelengths.

Now according to Rayleigh law of scattering, the intensity of light of wavelength $\lambda $ present in the scattered light is inversely proportional to the fourth power of $\lambda $ , provided the size of scattering particles is smaller than $\lambda $ , Mathematically
$scattering \propto \dfrac{1}{{{\lambda ^4}}}$

Different colours have different wavelengths. So, a white light on scattering gives a band of seven colours which is called the visible spectrum. Now, we know that the order of visible spectrum is Violet, Indigo, Blue, Green, Yellow and Red (VIBGYOR) that is Violet colour appears at the bottom or we can say that it is the most scattered. So, according to Rayleigh’s Law, we see that violet has the shortest wavelength. (Scattering is inversely proportional to wavelength)

Hence, option C is the correct answer.

Additional information:
The bluishness of sky and reddishness of the sky can be explained by Rayleigh’s Law. Blue colour has the shortest wavelength so it is scattered in all directions by small particles thus the sky appears blue while red colour having the longest wavelength is scattered by larger particles like dust, also during sunrise and sunset, light has to travel larger distance due to which blue, violet and other colours are completely scattered away and only red and yellow colour reaches our eyes that’s why the sky appears reddish during sunrise and sunset.

Note:Rayleigh scattering is the result of the electric polarizability of the particles. Light is an electromagnetic wave so it has an electric and magnetic field oscillating perpendicular to the direction of light, the electric field of the light wave acts on the charges within a particle and makes them move at the same frequency. These particles then become small radiating dipoles whose radiation we see as scattered light.

Answer

Verified

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.

Which part of the spectrum has the shortest wavelength?

What is the shortest visible wavelength?