Q.4.    Why is sound wave called a longitudinal wave?

Answers (1)
R Ritika Kankaria

longitudinal waves are formed When oscillation is created parallel to the disturbance of the particles of the medium in the direction of propagation and since the sound waves also create oscillations in the particles of the medium parallel to the disturbance in the direction of propagation.

Therefore, sound waves are called a longitudinal wave.