Which term refers to a wave in which the particles vibrate perpendicular to the direction of travel?

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

Answer: (C)

The main idea is how the motion of the particles relates to the direction the wave travels. In a transverse wave, the particles move perpendicular to the direction of travel—for example, a wave on a rope lifts and lowers as the wave moves forward, and light waves oscillate electric and magnetic fields perpendicular to their direction of travel. In contrast, a longitudinal wave has particles moving back and forth along the same direction the wave moves, like air particles compressing and expanding in sound waves. Density and medium describe properties of the material or the substance the wave moves through, not how the particles vibrate. So the term that fits is transverse wave.