Which term describes a wave where the medium vibrates perpendicular to the travel direction?

• A. Longitudinal Wave
• B. Medium
• C. Density
• D. Transverse Wave

Answer: (D)

The main idea is how the medium moves in relation to the direction the wave travels. When the medium vibrates perpendicular to the travel direction, that pattern is a transverse wave. You can visualize it by wiggling one end of a rope: the rope moves up and down as the wave moves along the rope forward, so the vibrations are at right angles to the wave's forward motion. That up-and-down motion creates peaks and valleys, or crests and troughs, as the wave propagates.

If the medium were vibrating parallel to the direction of travel, the wave would be a longitudinal wave, where particles compress and then spread out along the path of the wave. The terms medium and density describe what the wave travels through or a property of the matter, not the motion pattern of the wave itself, so they don’t describe the type of wave.