When a longitudinal wave propagates through a medium in a forward direction, the particles of the medium move _____.

  1. Back and forth
  2. Up and down
  3. Sideways
  4. Both b and c


Transverse waves are characterized by the motion of particles of the medium in a direction perpendicular to that of wave propagation.

The correct answer is: Back and forth

    • Longitudinal waves cause the medium to move parallel to the direction of the wave.
    • In a longitudinal wave, the particles move back and forth about their individual equilibrium positions.
    • In transverse waves, the particles move up and down about their individual equilibrium positions.
    • So, the correct option is a.