TRANSVERSE WAVE: CHARACTERISTICS AND EXAMPLES - PHYSICAL - 2025

The transverse waves are those in which the oscillation occurs in a direction perpendicular to the direction of wave propagation. In contrast, longitudinal waves are waves in which the displacement through the medium occurs in the same direction as the displacement of the wave.

It should be remembered that waves propagate through a medium by virtue of the vibration they cause in the particles of said medium. So the direction of propagation of a wave can be parallel or perpendicular to the direction in which the particles vibrate. Therefore, the distinction between transverse and longitudinal waves is made.

The most typical example of a transverse wave is the circular waves that propagate across the surface of the water when a stone is thrown. Electromagnetic waves like light are also transverse waves. As for electromagnetic waves, it is the particular case that there is no vibration of particles as there is in other waves.

Even so, they are transverse waves because the electric and magnetic fields associated with these waves are perpendicular to the direction of propagation of the wave. Other examples of shear waves are waves that are transmitted along a string and S waves or secondary seismic waves.

characteristics

The waves, whether they are transverse or longitudinal, have a series of characteristics that determine them. In general, the most important characteristics of a wave are those that are explained below:

Wave amplitude (A)

It is defined as the distance between the farthest point of a wave and its equilibrium point. Since it is a length, it is measured in units of length (usually measured in meters).

Wavelength (λ)

It is defined as the distance (usually measured in meters) traveled by a disturbance in a given time interval.

This distance is measured, for example, between two successive peaks (the peaks are the farthest point from the equilibrium position at the top of the wave), or also between two valleys (the farthest point from the equilibrium position in the bottom of the wave) successive.

However, you can actually measure between any two successive points on the wave that are in the same phase.

Period (T)

It is defined as the time (usually measured in seconds) that it takes a wave to go through a complete cycle or oscillation. It can also be defined as the time a wave takes to travel a distance equivalent to its wavelength.

Frequency (f)

It is defined as the number of oscillations that occur in a unit of time, usually one second. Thus, when time is measured in seconds (s), frequency is measured in Hertz (Hz). The frequency is normally calculated from the period using the following formula:

f = 1 / T

Wave propagation velocity (v)

It is the speed at which the wave (the energy of the wave) propagates through a medium. It is usually measured in meters per second (m / s). For example, electromagnetic waves travel at the speed of light.

Propagation velocity can be calculated from wavelength and period or frequency.

V = λ / T = λ f

Or simply dividing the distance traveled by the wave in a certain time:

v = s / t

Examples

Electromagnetic waves

Electromagnetic waves are the most important case of shear waves. A particular characteristic of electromagnetic radiation is that, contrary to mechanical waves that require a medium to propagate through, they do not require a medium to propagate and can do so in a vacuum.

This is not to say that there are no electromagnetic waves traveling through a mechanical (physical) medium. Some transverse waves are mechanical waves, since they require a physical medium for their propagation. These transverse mechanical waves are called T waves or shear waves.

Furthermore, as already mentioned above, electromagnetic waves propagate at the speed of light, which in the case of a vacuum is of the order of 3 ∙ 10 ⁸ m / s.

An example of an electromagnetic wave is visible light, which is electromagnetic radiation whose wavelengths are between 400 and 700 nm.

Transverse waves in the water

A very typical and very graphic case of a transverse wave is the one that occurs when a stone (or any other object) is thrown into the water. When this happens, circular waves are produced that propagate from the place where the stone has hit the water (or the focus of the wave).

The observation of these waves allows us to appreciate how the direction of the vibration that takes place in the water is perpendicular to the direction of movement of the wave.

This is best seen if a buoy is placed near the point of impact. The buoy rises and falls vertically as the wave fronts arrive, which move horizontally.

More complicated is the movement of the waves in the ocean. Its movement involves not only the study of transverse waves, but also the circulation of water currents when the waves pass. For this reason, the actual movement of water in the seas and oceans cannot be reduced solely to a simple harmonic movement.

Wave on a rope

As already mentioned, another common case of a transverse wave is the displacement of a vibration by a string.

For these waves, the speed at which the wave travels down the stretched string is determined by the tension in the string and the mass per unit length of the string. Thus, the speed of the wave is calculated from the following expression:

V = (T / m / L) ^1/2

In this equation T is the tension of the string, m its mass, and L the length of the string.

References

1. Transverse wave (nd). On Wikipedia. Retrieved on April 21, 2018, from es.wikipedia.org.
2. Electromagnetic radiation (nd). On Wikipedia. Retrieved on April 21, 2018, from es.wikipedia.org.
3. Transverse wave (nd). On Wikipedia. Retrieved on April 21, 2018, from en.wikipedia.org.
4. Fidalgo Sánchez, José Antonio (2005). Physics and chemistry. Everest
5. David C. Cassidy, Gerald James Holton, Floyd James Rutherford (2002). Understanding physics. Birkhäuser.
6. French, AP (1971). Vibrations and Waves (MIT Introductory physics series). Nelson Thornes.