direction of propagation

Examples of direction of propagation in the following topics:

• Transverse Waves

  • Transverse waves propagate through media with a speed $\vec{v}_w$ orthogonally to the direction of energy transfer.
  • A transverse wave is a moving wave that consists of oscillations occurring perpendicular (or right angled) to the direction of energy transfer.
  • For transverse waves in matter, the displacement of the medium is perpendicular to the direction of propagation of the wave.
  • Transverse waves are waves that are oscillating perpendicularly to the direction of propagation.
  • The direction of propagation of this wave is along the t axis.

• Longitudinal Waves

  • Longitudinal waves, sometimes called compression waves, oscillate in the direction of propagation.
  • Longitudinal waves have the same direction of vibration as their direction of travel.
  • This means that the movement of the medium is in the same direction as the motion of the wave.
  • The difference is that each particle which makes up the medium through which a longitudinal wave propagates oscillates along the axis of propagation.
  • The wave propagates in the same direction of oscillation.

• Waves

  • A wave only moves mass perpendicular to the direction of propagation—in this case up and down, as illustrated in the figure below:
  • A wave can be transverse or longitudinal depending on the direction of its oscillation.
  • Transverse waves occur when a disturbance causes oscillations perpendicular (at right angles) to the propagation (the direction of energy transfer).
  • Longitudinal waves occur when the oscillations are parallel to the direction of propagation.
  • We notice that while it moves up and down it does not move in the direction of the wave's propagation.

• Polarization By Passing Light Through Polarizers

  • Polarization is the attribute that wave oscillations have a definite direction relative to the direction of propagation of the wave.
  • Polarization is the property of waves that allow them to oscillate in more than one direction, but that direction is relative to that of the direction the wave is traveling in.
  • For an EM wave, the direction of polarization is the direction parallel to the electric field.
  • The direction of polarization of an EM wave is defined to be the direction of its electric field.
  • The electric and magnetic fields are perpendicular to the direction of propagation.

• Energy Transportation

  • The force you feel from a wave hitting you at the beach is an example of work being done and, thus, energy being transfered by a wave in the direction of the wave's propagation.
  • Waves carry energy along an axis defined to be the direction of propagation.
  • Electromagnetic waves can be imagined as a self-propagating transverse oscillating wave of electric and magnetic fields .
  • This is a direct result of the equations above.
  • Electromagnetic waves can be imagined as a self-propagating transverse oscillating wave of electric and magnetic fields.

• Huygens' Principle

  • These wavelets spread out in the forward direction, at the same speed as the source wave.
  • He was able to come up with an explanation of the linear and spherical wave propagation, and derive the laws of reflection and refraction (covered in previous atoms) using this principle.
  • where s is the distance, v is the propagation speed, and t is time.
  • However, if that person where to open their door while playing music, you could hear it not only when directly in front of the door opening, but also on a considerable distance down the hall to either side. is a direct effect of diffraction.
  • The direction of propagation is perpendicular to the wavefront, as shown by the downward-pointing arrows.

• Water Waves

  • Although we often observe water wave propagating in 2D , in this atom we will limit our discussion to 1D propagation.
  • As long as the waves propagate slower than the wind speed just above the waves, there is an energy transfer from the wind to the waves.
  • In deep water, longer-period waves propagate faster and transport their energy faster.
  • We see a wave propagating in the direction of the phase velocity.
  • The wave can be thought to be made up of planes orthogonal to the direction of the phase velocity.

• The Production of Electromagnetic Waves

  • The creation of all electromagnetic waves begins with a charged particle.
  • All the above sources of electromagnetic waves use the simple principle of moving charge, which can be easily modeled.
  • Placing a coin in contact with both terminals of a 9-volt battery produces electromagnetic waves that can be detected by bringing the antenna of a radio (tuned to a static-producing station) within a few inches of the point of contact.
  • Electromagnetic waves are a self-propagating transverse wave of oscillating electric and magnetic fields.
  • The direction of the electric field is indicated in blue, the magnetic field in red, and the wave propagates in the positive x-direction.

• Standing Waves and Resonance

  • A standing wave is one in which two waves superimpose to produce a wave that varies in amplitude but does not propagate.
  • These waves are formed by the superposition of two or more moving waves for two identical waves moving in opposite directions .
  • Standing waves are found on the strings of musical instruments and are due to reflections of waves from the ends of the string. shows seven standing waves that can be created on a string that is fixed at both ends.
  • Standing waves on strings have a frequency that is related to the propagation speed vw of the disturbance on the string.
  • A standing wave (black) depicted as the sum of two propagating waves traveling in opposite directions (red and blue).

• Wavelength, Freqency in Relation to Speed

  • The frequency of a wave is the number of cycles per unit time -- one can think of it as the number of crests which pass a fixed point per unit time .
  • where v is called the wave speed, or more commonly,the phase velocity, the rate at which the phase of the wave propagates in space.
  • Finally, the group velocity of a wave is the velocity with which the overall shape of the waves' amplitudes — known as the modulation or envelope of the wave — propagates through space.
  • In , one may see that the overall shape (or "envelope") propagates to the right, while the phase velocity is negative.
  • This shows a wave with the group velocity and phase velocity going in different directions.