Physics
Physics
Problem
Identify the correct definition of a longitudinal wave. a) Particles of the medium vibrate perpendicular to the direction of wave propagation. b) Particles of the medium move forward with the wave, carrying energy and matter in the same direction. c) Longitudinal waves can transmit energy through empty space without requiring any medium. d) Particles of the medium vibrate parallel to the direction of wave propagation.Intuitive explanation
A longitudinal wave is all about the direction of particle motion relative to the direction the wave travels. The key insight is that particles in a longitudinal wave oscillate back and forth along the same line that the wave itself moves—not perpendicular to it. Think of a slinky being pushed and pulled along its length: the coils compress and stretch in the direction the disturbance travels. Sound waves are the classic example, where air molecules vibrate parallel to the sound's direction of propagation.
Intuitive explanation
A longitudinal wave is all about the direction of particle motion relative to the direction the wave travels. The key insight is that particles in a longitudinal wave oscillate back and forth along the same line that the wave itself moves—not perpendicular to it. Think of a slinky being pushed and pulled along its length: the coils compress and stretch in the direction the disturbance travels. Sound waves are the classic example, where air molecules vibrate parallel to the sound's direction of propagation.