Longitudinal Waves

Introduction

A wave is the movement that occurs in a medium from one point to another when a body comes in contact with it. For example, consider that when you throw a rock or stone into a river, patterns are created in a circular motion through the point where the rock hits the water. Here the stone is the body and the water is the medium, and the patterns that appear on the water’s surface are waves.

There are two types of waves which are Transverse and Longitudinal Waves.

Transverse Waves

Transverse wave is defined as a wave in which the particles of the medium move in the direction perpendicular to the wave. For example, consider When a string is placed horizontally in a room and a movement is introduced to the left end of the wave of string, then the energy moving on the string (ropes) moves from left to right, which causes simultaneous up and down movement on the string. This type of wave generated is a transverse wave. The characteristic of a transverse wave is that the motion of the particle is normal to the motion of the wave.

Longitudinal Waves

A wave consisting of a vibration or periodic disturbance occurring in the same direction as the wave motion. When we compress or release one end of a coil spring, we will experience a compression force in it. The coil of spring has a point which moves with the wave and returns in the same way. While on returning, it starts from the neutral position and then reverses its movement again. The movement of sound through air results in compression of the gas in the direction that sound waves travel as they oscillate back and forth. Seismic waves that are primarily are also longitudinal.

Longitudinal waves are defined as the waves in which the displacement of the medium is in the same direction of the movement of the wave.

Formula of Longitudinal Waves

The longitudinal wave is given by

y = displacement of point

x = distance travelled by point

t = time

c = speed of wave

= amplitude of oscillations

= angular frequency

Terms used in Longitudinal Waves

Crest

The wave crest is a point in the center that has the maximum upward (upward) displacement from the rest position.

Trough

The trough is exactly the opposite of the crest. The center point that has the maximum downward (negative) displacement from the rest position is called the trough.

Longitudinal Wave Example

There are many longitudinal wave examples from which some are given here.

Sound Wave

A sound wave is an example of a longitudinal wave and is produced by the vibratory motion of particles moving through a conductive medium. An example of longitudinal sound waves is the tuning fork. 

For sound waves, the amplitude of the wave is the difference between the maximum pressure created due to the wave and the pressure of undisturbed air. The speed of sound propagation depends on the type and composition of the medium and the temperature through which it is propagating.

Pressure Waves

The pressure wave is the propagation of disturbance in a medium due to variations in pressure.

Characteristics of Longitudinal Waves

Compression

Compression in a longitudinal wave is defined as a region where the particles of the wave are nearest to one another.

Rarefaction

Rarefaction in longitudinal waves takes place if the particles are apart from one another.

Wavelength

The length of a complete wave cycle is called wavelength of a wave. When a pattern repeats itself, it is called a wave. The pattern repeats itself regularly and periodically in space and time. It is determined from the distance from crest to crest or from trough to trough.

Amplitude

When the particle has a maximum displacement from the rest position, it is called the amplitude of the wave. The distance from the resting point to the peak or crest is the amplitude. The amplitude can be determined from the resting position to the trough position. It can also be determined as the distance of the line segment normal to the rest position and moving vertically upward from the rest position to point A.

Transverse and Longitudinal Waves

1. Transverse wave is defined as a wave in which the particles of the medium move in the direction perpendicular to the wave.

And Longitudinal waves are defined as the waves in which the displacement of the medium is in the same direction of the movement of the wave.

1. The movement of transverse wave is in the direction of the propagation of wave.

But the movement of longitudinal waves is in the direction normal to the propagation of waves.

1. Traverse waves contain trough and crest.

But longitudinal waves contain refractions and compression. 

Conclusion

A wave is the movement that occurs in a medium from one point to another when a body comes in contact with it.

There are two types of waves which are Transverse and Longitudinal Waves.

Transverse wave is defined as a wave in which the particles of the medium move in the direction perpendicular to the wave.

A wave consisting of a vibration or periodic disturbance occurring in the same direction as the wave motion.

The longitudinal wave is given by

There are many examples of longitudinal waves such as sound waves, pressure waves, etc.

Longitudinal waves contain refractions and compression.

The movement of longitudinal waves is in the direction normal to the propagation of waves.