In a longitudinal wave, the particle displacement is:

In a longitudinal wave, the particle displacement is:

• A. Parallel to the direction of travel
• B. Perpendicular to the direction of travel
• C. Circular around the path
• D. Random

Answer: (A)

In a longitudinal wave, particles move along the same line as the wave travels. The disturbance travels by compressing and rarefying the medium in the direction of propagation, so each particle oscillates parallel to that direction. A classic example is sound in air, where air molecules move back and forth along the path the sound is moving, creating regions of compression and tension as the wave passes. This is different from transverse waves, where the particle motion is perpendicular to the travel direction (like up-and-down motion on a rope). Circular motion or random motion aren’t characteristic of the basic longitudinal wave pattern. So the displacement aligns with the direction of travel.

In a longitudinal wave, particles move along the same line as the wave travels. The disturbance travels by compressing and rarefying the medium in the direction of propagation, so each particle oscillates parallel to that direction. A classic example is sound in air, where air molecules move back and forth along the path the sound is moving, creating regions of compression and tension as the wave passes. This is different from transverse waves, where the particle motion is perpendicular to the travel direction (like up-and-down motion on a rope). Circular motion or random motion aren’t characteristic of the basic longitudinal wave pattern. So the displacement aligns with the direction of travel.