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Question
Explain the phenomenon of dispersion of white light through a glass prism, using suitable ray diagram.
Solution
Splitting of light into its constituent colors is referred to as dispersion. When a narrow beam of white light falls on a triangular glass prism, the light of different colors have different refractive indices in the glass. However, the speed of light is the same irrespective of its colors. Different refractive indices of different colors of light lead to their different bending pattern. This causes splitting of white light into light of seven colors called as VIBGYOR. V= violet, I= indigo, B=blue, G=green, Y= yellow, O=orange, R=red.
The light of red color bends the least on passing through the prism and appears at the top while violet color bends through the maximum angle and appears at the bottom.
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