Question

What type of wave is sound?

longitudinal

light

surface

transversal

Answer 1

sound is a longitudinal wave due to mode of propergation.
sound wave actually move by compression and rarefaction that is they shrink together (compression) and extend (rarefaction) like a rubber band but in this case air particles

Answer 2

In this case, the particles of the medium move parallel to the direction that the pulse moves. This type of wave is a longitudinal wave.

Longitudinal waves are always characterized by particle motion being parallel to wave motion. A sound wave traveling through air is a classic example of a longitudinal wave.