scattering of light.ppt

A power point presentation on scattering of light.

1. A seminar presentation on -
Scattering of light
Presented by-
Dilip Bhuyan
Roll no-125
B.Sc 4
th
Semester
Department of Physics, Bahona College

2. Table of content
Introduction
History on scattering of light
How the light scattered
Types of scattering of light
Phenomenon of scattering of light
•Blue colour of sky
•White colour of clouds or fog
•Danger signal Red
•Sun & sky looks Red at sunrise & sunset
Conclusion
References
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3. Introduction
Scattering of light is the phenomenon of change in the direction of
light on striking a particular type of particle.
The phenomenon of scattering of light by smoke, dust, water
droplets and colloidal particles(1nm-1000nm) is known as Tyndall
effect.
Making the path of light visible.
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Scattering of light happen only because of the electromagnetic
interaction among photons and the particles of medium.
It must be the size of the particle is smaller then
the wavelength of the incident light

4. In 1928, Sir C.V Ramman discovered that when a beam of
coloured light entered a liquid, a fraction of light scattered by liquid
in different colour, which is known as Ramman effect.
History on light scattered
In 1870 , John Tyndall first give the concept of scattering of light
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In 1871, Lord Rayleigh first noticed this light scattering.

5. How the light scattered
Random reflection from a rough surface-
As the surface has more roughness
absorbs more energy from the light ray
and it will scatter in different direction
depending on the wavelength of light
ray.
Reflection through impurities present in volume-
When light is scattered by charged particle by
levelling the energy of the incident radiation and
the rest energy of the charged particle present.
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6. Types of scattering of light
1.Rayleigh or selective scattering
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•It is an elastic scattering( i.e. wavelength of the scattered
light is same as the incident light).
•Occurs when the radius of the scattering object is much
smaller then the wavelength of light i.e. r<<λ
•Shorter wavelength scattered much more then the longer
wavelength i.e.I∝λ
-4
•Blue sky in a sunnyday is an example of this type of
scattering.

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2.Mie scattering
•Particle dimension comparable to wavelength of radiation.
•It is also an elastic scattering .
•The clouds having water droplets look white is an example of this
type of scattering.
3.Electromagnetic scattering-
•It includes both the elastic light and inelastic light scattering
.
Electric light scattering includes-Rayleigh scattering & mie scattering.
Inelastic scattering includes-Compton scattering, Ramman scattering etc.

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Phenomenon of light scattering

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3. Red colour as a danger signal
oWavelength of red colour is
large , so it less scattered and
travel long distance.
2. White colour of clouds or fog
oLarge particle scatter large
wavelength.
oScattered all the incident ray &
it appears in our eyes as white.

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Conclusion
Scatteringtheoryisimportantasitunderpins
oneofthemostubiquitoustoolsinphysics,
almosteverythingweknowaboutnuclearand
atomicphysicshasbeendiscoveredby
scatteringexperiment,e.g.Rutherford’s
discoveryofthenucleus,thediscoveryofsub
atomicparticles(suchasquarks),etc.

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References
https://en.m.wikipedia.org
www.//youtube.be/q2s6Hy4h1zw
Internet
Reference books
A textbook of optics, by Dr.N. Subrahmanyam& Brijlal
New simplified physics, by S.L Arora

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