In which type of wave does the medium move back and forth perpendicular to the direction of travel?

In which type of wave does the medium move back and forth perpendicular to the direction of travel?

• A. Transverse wave
• B. Longitudinal wave
• C. Sound wave
• D. Surface wave

Answer: (A)

In a transverse wave, the particles of the medium move perpendicular to the direction the wave travels. So if the wave moves to the right, the medium oscillates up and down. This perpendicular motion to the direction of travel is the defining feature of transverse waves. By contrast, longitudinal waves have particles moving back and forth along the same line as the wave travels, creating compressions and rarefactions—like sound waves moving through air. Surface waves mix motion on the surface, with both up-down and side-to-side components, but the key point for this description is the motion that is perpendicular to the travel direction.

In a transverse wave, the particles of the medium move perpendicular to the direction the wave travels. So if the wave moves to the right, the medium oscillates up and down. This perpendicular motion to the direction of travel is the defining feature of transverse waves. By contrast, longitudinal waves have particles moving back and forth along the same line as the wave travels, creating compressions and rarefactions—like sound waves moving through air. Surface waves mix motion on the surface, with both up-down and side-to-side components, but the key point for this description is the motion that is perpendicular to the travel direction.