Page 3 - Lesson note scattering of light

journey of sun light only a little of the blue colour of the white light is scattered(most
of the blue light remain in it).Since the light coming from the over head sun has all
most all its components colours in the right proportion, there fore the sun in the sky
overhead appears white to us.

Tyndall effect
Tyndall effect:

The scattering of light by particles in its path is called tyndall effect.

When a beam of sun light enters a dusty room through a window, then its path

becomes visible to us. This is because the tiny dust particles present in the air of
room scatter the beam of light all around the room. And when this scattered light

enters into our eyes, we can see the beam of light.

Tyndall effect can also be observed, when sun light passes through the canopy of a
dense forest.

Tyndall discovered that when white light consisting of seven colours is passed

through a clear liquid having small suspended particles in it, then the bule colour of
white light having shorter wave length is scattered much more than the red colour

having longer wave length.

When light is scattered due to particles in its path, it is called Tyndall effect. The way
a beam of sunlight becomes visible when it passes through dust particles in a room,
when sunlight passes through a canopy of dense forest etc., are examples of Tyndall
effect.

In 1859, Tyndall discovered that when white light is passed through clear liquid
having small suspended particles, then the blue colour of white light has shorter
wavelength and is scattered more than the red colour that has longer wavelength.
The colour of scattered light depends on the size of particles

 It is due to the scattered large dust particles and water droplets in the atmosphere
that when white sunlight falls on them it is reflected in such a way that the scattered
light also appears white. Dust particles and water droplets in the atmosphere are
larger than the wavelength range of the visible light.
 The extremely small air molecules in the atmosphere scatter mainly blue light when
white sunlight falls on them. This is because blue colour has lower wavelength and is
much more by the air molecules.

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