Answer:
In a longitudinal wave, vibrations are parallel to the direction of the wave motion. In a transverse wave, vibrations are perpendicular to the direction of the wave motion.
Step-by-step explanation:
There are two types of waves, according to their direction of oscillation:
- Transverse waves: in a transverse wave, the direction of the vibrations is perpendicular to the direction of motion of the wave. These waves are characterized by the presence of crests (points of maximum positive displacement) and troughs (points of maximum negative displacement). Examples of transverse wave are electromagnetic waves.
- Longitudinal waves: in a longitudinal wave, the direction of the vibrations is parallel to the direction of motion of the wave. These waves are characterized by the presence of compressions (regions where the particle density is higher) and rarefactions (regions where the particle density is lower). Examples of longitudinal waves are sound waves.
Therefore, according to the definition above, we can now complete the sentence:
In a longitudinal wave, vibrations are parallel to the direction of the wave motion. In a transverse wave, vibrations are perpendicular to the direction of the wave motion.