Question

define sound wave and rarefaction​

Answer 1

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Rarefaction is the reduction of an item's density, the opposite of compression. Like compression, which can travel in waves (sound waves, for instance), rarefaction waves also exist in nature. A common rarefaction wave is the area of low relative pressure following a shock wave (see picture).

Answer 2

Explanation:

ANSWER :-

Sound Wave => One compression and one rarefaction together comprise a complete sound wave.

Rarefaction => A region of emptiness was created as it pulls the air particles towards left. This region of low density is called rarefaction.