Transverse wave: When the particles of the medium vibrate about their mean positions perpendicular to the direction of propagation, then the wave is called transverse wave. It is a wave vibrating at right angles to the direction of its propagation.
Explanation: In Figure a transverse wave is shown. The particles of the medium in transverse wave, move up and down and the wave travels in a horizontal direction. Small arrows on this wave represent the directions of motion of the different particles at any instant.
The points at A and E in the upper part of the wave show maximum displacement of particles. These points are called crests. Point C represents the maximum displacement of particles in the negative direction which is called trough. A transverse wave progresses as a series of crests and troughs.
Here, the directions of motion of particles is perpendicular to the direction of propagation of wave, hence it is a transverse wave.
(1) When a stone is thrown on water of a pond, it is seen that water particles oscillate up and down and this oscillation proceeds towards the edge of the pond. The wave produced in this type is called transverse wave.
(2) A stretched string fixed at both ends is pulled perpendicular to its length and is released, a wave is produced in the string [Figure 2]. It is observed that the particles in the string oscillate perpendicular to the direction of motion of the wave.
So, the wave produced in a stretched string is a transverse wave.