Some Important Aspects In Physics.

Dispersion of light:

This is the phenomenon of splitting of white light into its constituent colours (say when it passes through a glass prism) is called dispersion of light.

Rainbows:

Rainbow is the beautiful illustration of dispersion of light & is observed during the rainfall or after the rainfall or when we look at water fountain provided the sun is at the back of observer. It is formed due to the dispersion of light suffering refraction & reflection in the droplets present in the atmosphere.

Scattering of Light:

The process of radiating the light by atoms and molecules in all directions is known as scattering of light

Why Sky Appears Blue ?

When white light from the sun enters the earth a atmosphere, the scattering of different colours takes place due to interaction with large number of very small particles in the earths atmosphere. The wavelength of blue colour is much smaller than that of red colour. Therefore the intensity of the blue light scattered is much more then that of red colour. Thus the blue colour becomes the major colour when sky is clean & pollution free. Hence sky appears blue.

Why the clouds are overall white ?

The clouds consist of dust particles & water droplets. Their size is very large as compared to the wavelength of incident light from the sun so there is very little scattering of light. Hence the light which we receive through the clouds has all the colours of light .As a result of this , we receive almost white light, therefore the clouds are generally white.

Do you know ?

The sky will appear black in the absence of earths atmosphere as no colour is scattered in that situation. Twinkling of stars will be visible in day time in the absence of earths atmosphere, Sun light would we visible only if we look directly at the sun.