Question

Why are the longitudinal waves also called pressure waves

Answer 1

This is because propagation of longitudinal waves through a medium involves changes in pressure and volume of air, when compression and rarefaction are formed.

Longitudinal waves are waves in which the displacement of the medium is in the same direction as, or the opposite direction to, the direction of propagation of the wave. Mechanical longitudinal waves are also called compression waves, because they produce compression and rarefaction when traveling through a medium, and pressure waves, because they produce increases and decreases in pressure.

Answer 2

Longitudinal waves are called pressure waves because they involve change in pressure and volume of air