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Question
What is the difference between a compression and a rarefaction in a sound wave? Illustrate your answer with a sketch.
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Solution
A longitudinal wave consists of successive compression and rarefaction that is formed due to continuous to and fro motion of a vibrating object.
A compression is that part of a longitudinal wave in which the particles of the medium are closer to one another than they normally are, and there is a momentary reduction in volume of the medium. It is a region of high pressure and high density.
A rarefaction is that part of a longitudinal wave in which the particles of the medium are farther apart than normal, and there is a momentary increase in the volume of the medium. It is a region of low pressure and low density.
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