Question

why longitudinal waves are called sound waves ?give 2 points

Answer 1

A longitudinal wave is vibrating in the direction it travels. So, sound waves vibrate in the direction they move through a medium (air, liquid, etc.).

Answer 2

1 if the particles of a medium vibrate or oscillate to and fro about their equilibrium positions,
2 and along the direction of propagation of the disturbance,
then the wave is called longitudinal wave.