Question
Why is sound wave called a longitudinal wave?
Solution
Longitudnal waves travel in the form of compression and rarefactions. In the waves the individual particles of the medium move in a direction parallel to the direction of the propagation of the distirbance. The particles do not move from one place to another but they simply oscillate back and forth about their position of rest. This is exactly how a sound wave propagates. Hence, sound waves are longitudnal waves.
