Which characteristic defines a transverse wave as opposed to a longitudinal wave?

The defining characteristic of a transverse wave, as opposed to a longitudinal wave, is the direction of particle motion. In a transverse wave, particles of the medium move perpendicular to the direction in which the wave travels. This means that if the wave is moving horizontally, the particles of the medium will oscillate vertically.

In contrast, a longitudinal wave features particle motion that occurs in the same direction as the wave is traveling, creating compressions and rarefactions in the medium. Understanding this distinction is crucial for comprehending how different types of waves propagate through various media, impacting fields such as optics, acoustics, and other areas of physics.

For clarity, other characteristics such as wave speed, wave amplitude, and wave wavelength do not inherently define whether a wave is transverse or longitudinal. They can vary independently of the particle motion direction and do not determine the classification of the wave type itself.