Wave Interactions

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Wave Interactions
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Wave Interactions

• Interference
• When two or more waves of the same type are
  combined at the same place at the same time.
• Interference Pattern
• Two dimensional representation of two periodic
  waves that occupy the same region

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The Superposition Principle

• Principle of Superposition
• Adding displacements of overlapping waves.
• Constructive Interference
• Wave that results from waves that are added
  together when the wavelengths are the same and
  are in phase.

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The Superposition Principle

• Destructive Interference
• Wave that results from waves that are subtracted
  when the wavelengths are not the same and are not
  in phase.

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Standing Waves

• A result of reflections of waves ( p. 373)
• Nodea point on the wave that is stationary on a
  standing wave
• In phasewhen crests and troughs overlap
• Out of phasewhen a crest overlaps a reflected
  trough

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Applications of Wave Interference

• Light (optics)
• Interference pattern has a series of bright and
  dark regions (bands)
• Bright regions are constructive interference
• Dark bands are destructive interference
• Sound (acoustics)
• Beats occur when frequencies are different
  (destructive interference)

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Resonance

• When the frequency of a forced vibration matches
  the natural frequency of an object making it
  vibrate with increasing amplitude
• Forced vibrationwhen an object is forced to
  oscillate at the frequency of the applied force