Which statement describes a compression wave?

Which statement describes a compression wave?

• A. It is a wave where particles move perpendicular to travel
• B. It is a wave where particles move back and forth along the direction of travel
• C. It is caused by vibrations in a vacuum
• D. It has no energy

Answer: (B)

A compression wave is a longitudinal mechanical wave, where the medium’s particles oscillate in the same direction as the wave travels. As the wave moves, regions of compression (particles packed together) and rarefaction (particles spread apart) propagate along the medium. This is why the statement that particles move back and forth along the direction of travel describes a compression (longitudinal) wave. In contrast, transverse waves have particles that move perpendicular to the direction of travel, like light or waves on a rope. A vibration in a vacuum cannot propagate as a mechanical wave because there is no medium to carry the vibrations, and a wave that has no energy contradicts how waves transfer energy.

A compression wave is a longitudinal mechanical wave, where the medium’s particles oscillate in the same direction as the wave travels. As the wave moves, regions of compression (particles packed together) and rarefaction (particles spread apart) propagate along the medium. This is why the statement that particles move back and forth along the direction of travel describes a compression (longitudinal) wave.

In contrast, transverse waves have particles that move perpendicular to the direction of travel, like light or waves on a rope. A vibration in a vacuum cannot propagate as a mechanical wave because there is no medium to carry the vibrations, and a wave that has no energy contradicts how waves transfer energy.