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How did Newton show that white light of ...

How did Newton show that white light of the Sun (sunlight) contains seven colours using two identical glass prisms?

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Newton showed that reverse of dispersion of light is also possible.
Newton kept two identical glass prisms close to each other one in an erect position and the other in an inverted position.

White light of the Sun (sunlight) gets dispersed when it passes through first prism `P_(1)`. This allowed all the colours of the spectrum to pass through the second prism.
The second prism `P_(2)` receives all the rays of seven colours from first prism and recombines them into the original white light.
This observation gave Newton the idea that the sunlight is made up of seven colours.
Any light that gives a spectrum similar to that of sunlight is called white light.
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Explain with appropriate diagram Newton's experiment showing that white light of the Sun (sunlight) is composed of seven colours.

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Knowledge Check

  • Splitting of white light into its seven constituent colours is called ………….

    A
    refraction
    B
    reflection
    C
    dispersion
    D
    interference

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