Longitudinal waves cannot travel through
(1) Vacuum
(2) Solid
(3) Liquid
(4) Gas
Answer: (1) Longitudinal wave cannot travel through a vacuum because such wave requires a medium such as solid-liquid or air to travel through. They cannot travel through a vacuum or in space. Longitudinal waves, also known as “l-waves”, are waves that have the same direction of vibration as their direction of travel, which means that the movement of the medium is in the same direction as, or the opposite direction to, the motion of the wave. Mechanical longitudinal waves are also called compressional waves or compression waves. Longitudinal waves include sound waves (vibrations in pressure, particle displacement, and particle velocity propagated in an elastic medium) and seismic P-waves (created by earthquakes and explosions).
