Sabtu, 28 Juli 2012

Transverse Waves


The waves are the movement of a distortion of a material or medium, where the individual parts or elements of the material only move back-and-forth, up-and-down, or in a cyclical pattern. The waves requiring a medium are called Mechanical Waves and those which do not require a medium are called Non Mechanical Waves.

Methods of energy propagation in which disturbance propagates with definite velocity without changing its form, is called Mechanical Wave. Energy and momentum propagates by motion of particles of medium. But medium remain at previous position, mass transfer does not take place. Propagation is possible due to property of medium viz. elasticity and inertia. The mechanical waves are basically of two types- Transverse waves and Longitudinal waves

Transverse Waves Definition

A wave motion, in which the particles of the medium oscillate about their mean positions at right angles to the direction of propagation of the wave, is called transverse wave. 

In a transverse wave the medium has particles that vibrate in a direction perpendicular to the direction of the propagation of wave. Here the formation of crest and trough takes place. The polarization of transverse wave is possible.
These waves can propagate through solids and liquids but not through gases, because gases do not possess elastic properties. Examples of these waves are: vibrations in strings, ripples on water surface and electromagnetic waves.
In a transverse wave the particles of the medium oscillate in a direction perpendicular to the direction of propagation as shown in the figure. For example if a given transverse wave moves in x direction then the oscillations will occur in the y รข€“ z plane.





Types of Transverse Waves

There are two types of transverse waves. Although scientifically there is no classification but for the purpose of understanding transverse waves are divided into two types:

  1. Electromagnetic Wave
  2. Polarized Waves


Electromagnetic Wave: The existence of medium is not essential for propagation. Periodic changes takes place in electric and magnetic fields hence, it is called electromagnetic wave. In vacuum, E.M waves travel with light velocity. Electromagnetic waves can be polarized and it can be transverse in nature. Medium is not required for propagating the E.M waves. Electromagnetic waves have momentum. Example: Radio waves, light waves, thermal radiation, X ray etc.


Polarized Wave: A two dimensional wave can be called a polarized wave. A two dimensional wave exhibits the process or phenomenon of polarization. The waves can also be linear polarized. If we move our hand in a line, up and down then we can achieve a polarized wave.

There can also be a circular polarized wave.For example: when we move our hand in a circular fashion we can get a circular polarized wave.

There is also a wave called an elliptically polarized wave. Such a wave can be formed by moving the hand in a combination of linear and circular motion. This is because of the motion in two dimensions.



Transverse and Longitudinal Waves


There are lots of differences between transverse and longitudinal waves. Some of them we have listed here in points.

  1. For longitudinal wave the vibration of the particles of the medium are in the direction of wave propagation while in transverse waves the particles of the medium vibrate in a direction perpendicular to the direction of propagation of wave.
  2. A longitudinal wave proceeds in the form of compression and rarefaction which is the stretch and compression in the same direction as the wave moves. While for a transverse wave the wave travels using crest and troughs which is the up and down motion of particles perpendicular to the motion of wave.
  3. For a longitudinal wave at places of compression the pressure and density tends to be maximum, while at places where rarefaction takes place, the pressure and density are minimum.
  4. In gases only longitudinal wave can propagate.
  5. Longitudinal waves are also called compression waves.
  6. Examples of longitudinal waves are sound waves, tsunami waves, earthquake P waves, ultra sounds, vibrations in gas, and oscillations in spring, internal water waves, and waves in slink etc.
  7. The examples of transverse waves are light waves, all the electromagnetic waves, audience waves, magnetic waves, surface waves, S earthquake waves, ultraviolet waves.



S Waves

S wave basically moves through the body of the object rather than its surface. The ones that move through the surface are called surface waves. S wave is basically a transverse or shear wave. The motion of the particles is perpendicular to the direction of propagation of wave. The S wave can be compared to the rope waves. The p waves are like waves in a slink. The shearing effect provides the necessary restoring forces. The continuity equation for the incompressible media is followed by S waves. There is no divergence in these waves. S in s-wave means secondary waves. They are called so as they are the second to arrive and not the first during the earthquake. Polarization and birefringence are some of the properties of S waves. These are similar to transverse waves. 


Examples of Transverse Waves

There are various examples of transverse waves. They are:
  1. light wave is an example of transverse wave.
  2. The audience wave is an example of transverse wave.
  3. The secondary as well as magnetic waves are an example of transverse wave.
  4. Radio waves are also transverse waves.
  5. Television waves are transverse waves.
  6. In gas and liquid the sound waves are transverse waves.
  7. Surface waves are transverse waves.
  8. The visible light waves are transverse waves.
  9. Water wave is a transverse wave.
  10. S- waves are transverse waves
  11. Ultraviolet waves travel as transverse waves.
  12. The vibrating guitar strings are also an example of transverse waves.
  13. Doing the ‘wave’ at the stadium is another example.
  14. Gamma rays are another example.
  15. The x rays are also electromagnetic as well as transverse in nature.
  16. The radio and microwave is example of transverse waves.
  17. Heat is an example of transverse wave.