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wave

Tags
phys/light
phys/wave
sec/5
cegep/3
Word count
280 words
Reading time
2 minutes

Travelling oscillating disturbance that carries energy without transfer of mass

[!abstract] wave pulse
Single disturbance, e.g. one jerk of a rope

[!abstract] periodic wave
Continuous stream of pulses

Properties

Wavelength

Distance between two successive identical points
Sym. λ

Amplitude

Maximum displacement of particles
Sym. A

Frequency

Number of peaks that pass through a point in one second
Ant. period

f=1T

Period

Time taken for one peak to pass through a point
Ant. frequency

T=1f

Speed

Travelled distance per time
Property of the medium (determined by the restoring force and the inertia)

v=FrestoringIv=λTv=λf

For a wave propagating along a string under tension:

v=Tsμμ=ml

Where μ is the linear density in kg/m.

Wave speed != speed of particle

Direction

Transverse: motion of medium perpendicular to direction of propagation
Longitudinal: motion of medium parallel to the direction of propagation

Types

  • Mechanical
  • Electromagnetic
  • Gravitational
  • Matter

Mechanical

Propagates through a physical medium

[!example] Sound, ocean wave

Electromagnetic

Propagate through the electromagnetic field

[!example] Light, radio

Representation

Snapshot: displacement as a function of position at a given moment in time
History graph: displacement as a function of time at a given point in space
3D: both time and space

+

The leading edge is in the direction of the wave in snapshot.
The leading edge always comes first (left) in history graph.
=> the snapshot and the history graph are reversed for a wave going right.

Contributors

Changelog