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White light is passed through a prism to yield a spectrum.
(a) The ray of which colour will show the maximum angle of deviation and which one will show the least angle of deviation?
(b) A blue-coloured ray is passed through a glass prism. What will be the colour of the emergent ray? Justify your answer.
Answer:
(a) The angle of deviation is indirectly proportional to the wavelength of light passing through it - longer the wavelength, smaller the deviation .
Therefore,
- Maximum angle of deviation - Violet colour ray
- Minimum angle of deviation - Red colour ray
(b) The emergent ray will be blue in colour.
White light passing through a prism undergoes dispersion .
But a blue colour ray cannot be split any further . it will pass through the prism undispersed.
