Physics Complete: Wave Motion and its Variables

The wavelength is the minimum distance between any two identical points on adjacent waves.

period is the time required for two identical points (such as the crests) of adjacent waves to pass by a point.

The frequency of a periodic wave is the number of crests (or troughs, or any other point on the wave) that pass a given point in a unit time interval. The maximum displacement of a particle of the medium is called the amplitude A of the wave.

Waves travel with a specific speed, and this speed depends on the properties of the medium being disturbed.

A traveling wave that causes the particles of the disturbed medium to move perpendicular to the wave motion is called a transverse wave.

Example

Let us consider to flick one end of a long rope that is under tension and has its opposite end fixed, as shown in figure below. A single wave bump is formed and travels along the rope with a definite speed. This type of disturbance is called a traveling wave, and figure represents four consecutive “snapshots” of the creation and propagation of the traveling wave. The rope is the medium through which the wave travels.

A single pulse, in contrast to a train of pulses, has no frequency, no period, and no wavelength. However, the pulse does have definite amplitude and definite speed. The properties of particular medium that determine the speed of the wave are the tension in the rope and its mass per unit length. The shape of the wave pulse changes very little as it travels along the rope.

A traveling wave that causes the particles of the medium to move parallel to the direction of wave motion is called a longitudinal wave.

Example

The left end of the spring is pushed briefly to the right and then pulled briefly to the left. This movement creates a sudden compression of a region of the coils. The compressed region travels along the spring .The compressed region is followed by a region where the coils are extended. The direction of the displacement of the coils is parallel to the direction of propagation of the compressed region.

Sound waves are another example of longitudinal waves. The disturbance in a sound wave is a series of high-pressure and low-pressure regions that travel through air or any other material medium.