Tuesday, August 28, 2012

How does rainbow happen?

                                                   How does rainbow happen?                           

Rainbow always happen to the opposite direction of Sun. It can happen either in east or west direction. But not in north or south direction since Sun will not be seen in those direction.
The reason for rainbow is the refraction principle of physics. As we have studied in 2nd PUC, the principle of refraction is very simple. When a beam of light rays passed through a sphere, it will divide into 7 colours namely Violet, Indigo, Brown. Green , Yellow, Orange and Red. Red always as the last colour since its wavelength is small as compared to Violet which comes first.
Now in the morning, when Sun rises in east and when sunrays comes at an angle of 45 degrees, that time if there is rain is coming, then sunrays passes through these droplets of rain which acts as a sphere and get refracted thus giving rise to 7 colours. Hence rainbow occurs in west. Same happens when Sun is going to set in west direction and rainbow occurs in east direction.
It is the main principle behind rainbow and why it is not seen in north or south direction.

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