Scattering of light

Light can be examined entirely from its source. When light passes from one medium to anothersay aira glass of waterthen a part of the light is absorbed by particles of the mediumpreceded by its subsequent radiation in a particular direction. This phenomenon is termed a scattering of light. The intensity of scattered light depends on the size of the particles and the wavelength of the light.

Shorter wavelength and high-frequency scatter more due to the waviness of the line and its intersection with a particle. The wavier the linethe more the chance it intersects with a particle. On the other handlonger wavelengths have low frequencythey are straighterand the chances of colliding with the particle are lessso the chances are less.

The bending of multicoloured light can be seen in the afternoon due to the refraction and total internal reflection of light. The wavelength of the sunlight forms different colours in different directions. Rayleigh scattering theory is reasoned for the red colour of the sun in the morning and the blue colour of the sky.

Let p be considered as the probability of scattering and λ is the wavelength of radiationthen it is given as:

The probability for scattering will give a high rise for a shorter wavelengthand it is inversely proportional to the fourth power of the radiation wavelength.

Why Is the Colour of the Clear Sky Blue? And Why Are the Clouds White?

Molecules with a larger size than the wavelength of light experience the scattering effect differently; the phenomenon is known as the Mie effect. Due to the largeness of particlesthe light appears white. That is why the cloudswhich are made of water dropletsare white. The blue colour is present in the major percentage of the lower wavelengths. With the wavelength of the lightthe scattering efficiency of the small molecules in the atmosphere decreases. Sun radiates its lightand its rays fall into the earth’s envelope thussunlight gets scattered in the atmosphere.

Some examples also show scattering; particles like dust and smoke can also scatter radiation. In the same mannerwe can explain the red colour appearance of the sun. For red lightthe wavelength is moreand it is easy to go through the atmosphere as the scattering is less for red light. When the light is on any other objectit gets scattered depending on its properties as different light has different intensitiesand each particle has different characteristics.

Frequently Asked Questions – FAQs

Q1

What is light?

Light (visible light) is a type of electromagnetic radiation within the section of the electromagnetic spectrum observed by the human eye.

Q2

Explain the concept of scattering of light.

When a light beam goes through a mediumit hits the particles existing in them. Due to this phenomenonsome light rays get absorbed while a few get scattered in various directions. The intensity of the scattered light rays depends on the particles’ size and wavelength.

Q3

What is meant by total internal reflection?

Total internal reflection is an optical phenomenon that happens when the light rays propagate from a more dense medium to a much lesser dense medium. This type of reflection only happens when the angle of incidence is greater than a particular limiting angle known as the critical angle.

Q4

Why is the colour of the sky blue?

Particles and gases in the Earth’s atmosphere scatter sunlight in every direction. Blue light is much more scattered than any other colour because it propagates as smallershorter waves. This is the reason why the sky is blue most of the time.

Q5

What was the most famous discovery of C V Raman?

Raman effect of scattering.

Watch the video and solve the previous year questions in the chapter The Human Eye and Colorful World Class 10

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