Page 1 - Lesson note recombination of white light

SAI INTERNATIONAL SCHOOL
PHYSICS
CLASS X
Chapter: LIGHT(Human eye and the colourful world)
MODULE-38

LESSON NOTES: dispersion through prism, recombination of light, rainbow

Dispersion of light
In 1665, Isaac Newton discovered that white light consists of seven colours. He
found that if a beam of white light is passed through glass prism then it will split in to
seven colours. These colours are red, orange, yellow, green, blue, indigo and violet
(VIBGYOR).

Spectrum of white light: The band of seven colours formed when a beam of white
light is passes through a glass prism is called spectrum of white light.
Dispersion of light: The splitting of white light into seven colours on passing
through a transparent medium is called dispersion of light.
Cause: The dispersion of white light happens because the angle of refraction of
lights of different colours is different while passing through the transparent medium.

For example, red colour deviates least and is formed at the upper part of the
spectrum and violet colour is deviated maximum and is formed at the bottom of the
spectrum.

Recombination of spectrum of colours

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