Wave transfers energy from one point to another, often with no permanent displacement of the particles of the medium that is, with little or no associated mass transport. Waves are described by a wave equation which sets out how the disturbance proceeds over time.
Types of wave
This type of wave motion requires material medium to propagate. For example ripples on water surface, vibration of a stretched string, sound wave, shock wave generated by a supersonic jet plane, seismic wave generated during earth quake.
Radiant energy like visible light, x-ray, infrared ray, micro wave etc. are simultaneous oscillations of electric and magnetic field. This type of wave can propagate without any material medium.
Transverse and longitudinal waves:
Waves are again classified into two groups according to the direction of vibration of the medium particles with respect to the direction of wave propagation. In transverse waves the particles vibrate in a direction perpendicular to the direction of wave propagation. Examples: vibration of stretched string, all electromagnetic waves;