what is wave

Wave:

   A wave can be described as a disturbance that travels through a medium from one location to another location.

Wave is a variation or disturbance which travels thru a medium. Waves are characterised by parameters like wavelength, frequency, speed. Waves can be classified into electromagnetic wave & mechanical wave on the basis of medium of travel. Also it can be classified on the basis of particle displacement into longitudinal waves & transverse wave.

Waves that do not require a medium for propogation are called electromagnetic waves whereas waves that require medium for propogation are called mechanical waves. 

Electromagnetic waves include gamma ray, X-ray, visible light, microwave, radio wave.

Mechanical waves include sound wave, ocean wave, oscillation of spring.

If the particle displacement is parallel to the direction of wave propogation, such waves are called longitudinal waves. Eg: Sound wave...

If the particle displacemnt is perpendicular to the direction of wave propogation, such waves are transverse waves. Eg: Light wave