Does Longitudinal Wave Travel: How, Why And Detailed Explanations


We will study and understand the different aspects of does longitudinal wave travel and its detailed explanations in this article.

The longitudinal wave does travel. It is a movement of all the minute particles together in a parallel path in a medium; all these particles vibrate in a parallel path to the direction in which the wave travels. This type of movement of waves in a parallel direction is considered longitudinal waves.

To understand the detailed explanations of how does longitudinal waves travel in a medium.

How longitudinal waves travel?

A longitudinal wave is a mechanical wave that always requires some medium to pass through.

When passed through a matter, these longitudinal waves move in a parallelly aligned direction in consideration of the direction of wave motion. An excellent example of a longitudinal wave is sound waves, and these sound waves require an air medium in which the atoms vibrate while moving from source to receiving end. During this movement, the atoms undergo vibration in the air medium, and they move back and forth in the same direction of wave and opposite to the path of transfer of energy.

Therefore, we can consider that all the longitudinal waves can travel with a particular medium.

Do longitudinal waves travel at the speed of light?

Longitudinal wave does not travel at the speed of light, and only the transverse waves can travel at light speed.

  • The only type of waves that matches the speed of light while propagating is electromagnetic waves. The electromagnetic waves propagate in a normal path to the wave motion. So, it comes under transverse waves.
  • Transverse electromagnetic waves are faster; other transverse waves propagate with less velocity than longitudinal waves.
  • Except for these, the other waves cannot match the speed of light. Usually, the longitudinal waves move at the speed range between 0.2 miles to Several Kilometer, depending on the type of medium. Hence, we can say that longitudinal waves do not travel at the speed of light.

Now let us know about the comparison of propagation speed between transverse and longitudinal waves.

Do longitudinal waves travel faster than transverse?

Except for electromagnetic and gravitational transverse waves, all the other transverse waves travel less than longitudinal waves.

All the transverse waves pass in a normal direction concerning wave direction, whereas longitudinal waves propagate in parallel paths. Both waves consist of particles that undergo vibration while traveling.

In the case of transverse waves, this vibration of the particle in the normal path acts as a resistance, and it occurs due to the perpendicular propagation of waves. This resistance reduces the speed of waves, which makes them travel with less speed than the longitudinal waves.

does longitudinal wave travel
Image Credit: Image by flickr, CC BY 2.0

Both waves are generated during the earthquake; in this case, the longitudinal waves always move with more speed than transverse waves.

Even in any solid matter, the transverse’s movement is prolonged compared to longitudinal waves.

Now to study whether electromagnetic waves are truly transverse or longitudinal waves.

Are longitudinal waves electromagnetic?

Electromagnetic waves come under transverse mechanical waves since they propagate perpendicularly to the wave propagation path.

When we talk about electromagnetic waves, we have two consider the two essential components and their path of propagation, i.e., electric and magnetic fields. Both the field generally travels to one another.

If we consider them as longitudinal waves, then the aspect of polarization which is the critical phenomenon of electromagnetic waves, cannot be observed.

So, for the occurrence of polarization phenomenon, these electromagnetic waves travel perpendicularly and are transverse waves. It can never be a longitudinal wave.

To understand the different propagation mediums of a longitudinal wave.

How does longitudinal wave travel in space medium?

Space medium can also be considered the same as vacuum medium, and in the space medium, we cannot find even a tiny amount of matter that helps the waves pass through it.

Let us understand it considering the divergence of both electric and magnetic fields. We already know that the waves travel in a parallel path in longitudinal waves. If you calculate the divergence value to this movement, the result will be zero because these waves do not occur in space, and the divergence of both electric and magnetic fields will be zero.

We get the value of divergence as zero because the direction of movement of k-vector in a longitudinal wave is always orthogonal to electric and magnetic fields.

Therefore, we can infer from the above that longitudinal wave does not travel in space medium.

What is the mode of displacement for a longitudinal wave?

The displacement of longitudinal waves tells about nothing but how the longitudinal waves travel in a medium.

In the above sections, we have learned that all the longitudinal waves from the shortest range to the longest range waves need some matter to travel.

They always propagate similarly to the wave movement, and whether we observe in any of one, two, or three-dimensional views, we can observe the same displacement.

In the next part of this post, let us interpret the fastness of both transverse and longitudinal waves.

How can you interpret that longitudinal waves travel faster than transverse?

We can explain the vastness of both the transverse and longitudinal waves by considering their propagation path.

If we consider transverse waves, the vibration of particles in these waves generally occurs in the typical path to the wave motion; it acts as a resistance and occurs due to the perpendicular propagation of waves. This resistance reduces the speed of waves, which makes them travel with less speed than the longitudinal waves.

But in longitudinal waves, as the propagation of particles will be parallel to wave movement direction, it won’t experience any such resistance. It will be free to move, which gives it the required speed.

Always longitudinal waves will have more speed than transverse waves except in some cases.

How does longitudinal wave travel in the string?

The longitudinal waves travel in parallel propagation even in the string.

We can find out both transverse and longitudinal mechanical waves in a string. But if we try to measure the velocity of these waves, then obviously, the longitudinal waves move a little faster than transverse waves.

These longitudinal waves won’t face any significant impact during the string tension, and there will be only very minute changes in propagation and speed.

Now to see how to calculate longitude waves using a formula.

How to calculate longitudinal waves using the formula?

One important wave measurement is used in physics to calculate the value of longitudinal waves in motion. The formula is mentioned as below,

y(x,t)=yocos[ω(t−xc)]

It can also be written in simple manner as shown,

y(x,t)=yocos[w(t-x/c)]

In the above formula, the terms refer as written below,

  • y refers to the movement of the point on the traveling longitudinal wave
  • x indicates how much distance a specific point has traveled from the source where wave generates
  • t indicates the time elapsed
  • yrefers to the amplitude of the wave oscillations that give brief about the loudness and intensity of the wave
  • c indicates the speed of the longitudinal wave
  • ω is the term used to refer to the angular frequency of the longitudinal wave

It is one of the essential formulas used to calculate longitudinal waves.

List out the different examples of longitudinal waves?

The different examples of longitudinal waves that are important to be known are written below,

While you clap your hands for appreciation

When you clap your hands on any suitable occasion of appreciating others’ work, the sound you hear on clapping is heard due to the vibration of particles in the medium; these particles move parallel to one another, indicating they are longitudinal waves.

does longitudinal wave travel
Image Credit: Pixabay free images

Music Woofers used by DJ

If you carefully look at the musical woofer used by a DJ, you will notice that whenever there is an increase or decrease in sound, the cone of the musical woofer moves in and out. It happens due to waves created because of the vibration of particles. The waves produced here are longitudinal waves that travel between air mediums.

does longitudinal wave travel
Image Credit: Pixabay free images

Shaking of window panels after thunder

When there is thunder and storm, the windows of our household vibrate for a fraction of time. When the lighting intensity is increased, the air pressure increases automatically, leading to a slight increase in the atmospheric temperature. All these aspects together create a sound wave that we hear as thunder, because of which the window panels will vibrate. The louder the sound, the amplitude of these waves will be maximum. The window panels will vibrate only due to the sound waves created due to the vibration and transfer of particles.

does longitudinal wave travel
Image Credit: Pixabay free images

The above three are the primary examples of longitudinal mechanical waves that tell how it transports in a medium.

Read More: How to find wavelength of transverse waves

Frequently Asked Questions | FAQs

Can we consider all the longitudinal waves to be mechanical?

If we consider the components of mechanical waves, there will be three main parts longitudinal, transverse, and sometimes even surface waves.

All the different longitudinal waves come under the mechanical wave, and the only difference is they travel through a different medium. According to the matter they chose to travel, they are named respectively.

Do longitudinal waves need a medium to propagate?

Wave is generally the movement of particles in a particular order.

Longitudinal waves come under the category of mechanical waves, which undergo propagation through some vibration of particles of atoms present in the medium. If there is a medium’s absence, it will be impossible for the propagation purpose to indicate that longitudinal waves need a medium to travel.

What is the significant difference between longitudinal wave and transverse wave?

The significant difference between a longitude wave and a transverse wave lies in the path they propagate.

In a transverse wave, the vibration and movement of particles will always be along the normal direction to the wave movement. In longitudinal waves, we can observe the propagation in the same path and parallel to the wave movement.

How can we use longitudinal waves in our everyday routine?  

The pressure and sound waves are the essential waves that propagate longitudinally. The many ways we can make use of these longitudinal waves are,

  • The music we listen to is with the help of sound waves.
  • In a string used to hold objects, longitudinal waves are produced.
  • While playing any instrument, sound waves are produced.
  • The intensity of pressure waves helps to determine the impact of the earthquake.
  • Similarly, even the measure of the waves hitting the seashore helps estimate its intensity.

Raghavi Acharya

I am Raghavi Acharya, I have completed my post-graduation in physics with a specialization in the field of condensed matter physics. Having a very good understanding in Latex, gnu-plot and octave. I have always considered Physics to be a captivating area of study and I enjoy exploring the various fields of this subject. In my free time, I engage myself in digital art. My articles are aimed towards delivering the concepts of physics in a very simplified manner to the readers. Let’s connect through - LinkedIn: https://www.linkedin.com/in/raghavi-c-s-260a801b1 EMAIL ID: raghavics6@gmail.com

Recent Posts