# Wave Motion

Waves are caused by vibration in a medium which carries energy from one point to another without a direct contact between the two points.

## Mechanical waves

Machenical waves are also known as elastic waves. These waves need a material medium for their propagation(travel). Sound waves and water waves are example of mechanical waves.

## Electromagnetic waves

These waves do not need a material medium to propogate(travel). They can travel even through vaccum, they travelles with a very high speed of 3 × 108 m/s.

## Transverse Waves

A wave in which the particles of the medium vibrate up and down(at right angles) to the direcction in which the wave is moving, is called a transverse wave. The water waves formed on the surgace of water in a pond are example of transverse wave.

## Longitudinal Waves

A wave in which the particles of the medium vibrates back and forth in the 'same direction' in which the wave is moving is called a longitudinal wave. The wave travelling along a spring when it is pushed and pulled are longitudinal waves.

## Pulse Waves

A waves set up by a single disturbance in the medium are called pulses. The formation of water waves on the surface of water when a stone is dropped into it is an example of wave pulses, the sound waves produced by te clapping og hands is also an example of wave pulss

## Periodic Waves

The waves which are caused by continuous disturbance in the medium occurring due to regular vibrations are valled periodic waves. Periodic waves are repeative in nature. When a periodic wave is formed, the medium oscillates for a long time after it is disturbed.

## Characterstics of Waves

To understand the concept of waves we must know the characterstics of waves. The main characterstics of waves are as follow:

1. Wavelength: The distance between two nearest points in a wave which are in the same phase of vibration is known as the wavelength.
2. Amplitude: The maximum height or distance moved by a point on a vibrating body or wave, measured from its equilibrium(central) position.
3. Time Period: The time required to produce one complete wave is called time period of the wave.The time taken to cimplete one vibration is called time period.
4. Frequency: The number of vibrations produced in one second is called frequency of the wave
5. Velocity of wave: The distance travelled by a wave in one second is called velocity of the wave. Velocity of wave = Frequency of wave × wavelength of wave