When we pass white light through a prism,

it splits into different colors


What is Dispersion?

Splitting up of white light into 7 different colors when passed through a transparent medium (like Glass Prism) is called Dispersion


When white light is passes through the prism, it splits into seven colors. They are

  • V iolet
  • I ndigo
  • B lue
  • G reen
  • Y ellow
  • O range
  • R ed


What is Spectrum?

Band of coloured components of light are called spectrum

Hence, 7 colors formed on dispersion of light is called spectrum

What causes Dispersion ?

White light is combination of these 7 colors

When light falls on a prism, it changes medium (from air to solid)

Hence, different colors of light bend at different angles

Red light bends the least while violet line bends the most

Hence, different rays of different color emerge along different paths

This causes dispersion of light



Recombination of Spectrum to give White Light


In this case 2 prisms are used together


Firstly sunlight light is made to fall on the prism

This makes white light to form spectrum of 7 colors

This spectrum is made to fall on another prism which was held in inverted position

This leads to emergence of sunlight from second prism




Note: - This method was first used by Isaac Newton


Note: - Any light that gives a spectrum similar to that of sunlight is
often referred to as white light.

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Maninder Singh's photo - Co-founder, Teachoo

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Maninder Singh

CA Maninder Singh is a Chartered Accountant for the past 14 years and a teacher from the past 18 years. He teaches Science, Economics, Accounting and English at Teachoo