Let us take one example, if you drop a pebble in still water, the water surface gets disturbed. This disturbance is not confined to one place but here the particles of water are moving up and down at their respective positions. But still there is something which moves outward, we call it a wave...
To make it simple, wave is a disturbance from equilibrium position which travels, but more substantially particles do not travel, it just oscillates about their mean positions. Primarily, waves are of two types:
Wave Diagram
1] Mechanical waves
Mechanical waves require a medium to transport their energy from one location to another. Sound waves require a medium(air) in order to propagate, thus sound waves are mechanical waves also since sound waves are incapable of traveling through vacuum. Waves on a string, waves in air column etc are called mechanical waves.
→ Types of mechanical waves:
a. Longitudinal wave
→The vibration of the particle is in the same direction as that of the direction of propagation of wave.
Example: sound wave, pressure waves etc are longitudinal waves.
b. Transverse wave
→The vibration of the particle is in the direction opposite to the direction of propagation of wave.
Example: Light wave, seismic waves, vibration in a string etc are transverse waves.
c. Surface wave
→A surface wave is something which travels along the surface of a medium. This waves usually occurs at the boundary of the two media.
Example: Waves in ocean is the example of such type of waves.
2] Non-mechanical waves
Waves which does not require a medium to transport their energy from one location to another are called non mechanical waves.
Example: Electromagnetic waves are non mechanical waves since it does not require any medium to propagate.Electromagnetic waves are waves which are produced due to the periodic vibration of two mutually perpendicular electric and magnetic fields.
Heinrich Rudolf Hertz proved the existence of the electromagnetic waves.
