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Question
Describe how you could demonstrate that white light is composed of a number of colours.
Solution
We can show that white light is composed of a number of colours by passing it through a transparent glass prism. A glass prism is a triangular refracting surface. When a beam of white light enters the prism, the light splits, forming a band of seven colours on a screen placed on the other side of the prism. This splitting of light into its constituent colours is called dispersion of light. The formation of seven colours in a spectrum shows that white light is composed of these seven colours, namely, red, orange, yellow, green, blue, indigo and violet.
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