In the simplest term, a wave can be defined as the continuous transfer of disturbance from one place to another with definite speed without the actual transfer of matter particle.
In wave motion:
- Particles of the medium vibrates in simple harmonic motion (to and fro, directed towards the mean position)
- Energy and linear momentum get transferred.
- All the particles of the medium vibrate with some amplitude, frequency and time period. e.g. Sound wave, water waves etc.
On the basis of transmission medium, there are two types of waves:
1. Mechanical wave: The wave which needs material medium for its propagation is called mechanical wave. For the propagation of this wave, the medium must have inertia, elasticity and less damping. e.g. : Sound wave, Vibration of strings etc.
2. Electromagnetic wave: The wave which does not need material medium for its propagation is called electromagnetic wave. These wave travels due to the variation of electric and magnetic field. All the electromagnetic waves are transverse and are polarized. Radio waves, microwaves, infrared waves, ultraviolet waves, X-rays, Cosmic rays are some of the electromagnetic waves. These wave have very high speed.
On the basis of modes of vibration, there are two types of wave:
1. Transverse wave: The wave in which the particles of the medium vibrate mutually perpendicular to the direction of propagation is called transverse wave. This type of wave is possible in media possessing elasticity in shape or rigidity. So, longitudinal wave can only travel through solid and surface of liquid. These types of wave motion travels in the form of trough or crest. The distance between two successive trough or crest is called the wavelength in case of longitudinal wave.
2. Longitudinal wave: The wave in which the particles of the medium vibrate along the direction of propagation of wave is called longitudinal wave.This type of wave is possible in media possessing elasticity of volume. So, transverse wave can travel through solid, liquid and gas. This type of wave travels in the form of compression and rarefaction. The distance between two successive compression or rarefaction is called wavelength.