A narrow beam PQ of white light is passing through a glass prism ABC as shown in the diagram.

Trace it on your answer sheet and show the path of the emergent beam as observed on the screen DE.
(i) Write the name and cause of the phenomenon observed.
(ii) Where else in nature is this phenomenon observed.
(iii) Based on this observation, state the conclusion which can be drawn about the constituents of white light.

i) The name of the phenomenon is dispersion of light. White light is comprised of seven colours. Dispersion of light occurs because these colors travel at different speeds through glass prism. Hence, different colors undergo different deviations on passing through prism.

ii) This phenomenon is observed in rainbow formation. Rainbow is caused due to dispersion of sunlight by water droplets present in the atmosphere. Rainbow is always formed in a direction opposite to the sun.

iii) The constituents of white light is a sequence of colours given by Violet, Indigo, Blue, Grren, Yellow, Orange and Red (VIBGYOR). Red light bends the least and violet light bends the most.

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