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Standing Waves. Standing waves are a special case of superpositioning Consider two waves traveling in opposite directions Equal in amplitude Equal in wavelength and frequency. Temporal and spatial components decoupled At certain points, wave vanishes for all times
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Standing Waves • Standing waves are a special case of superpositioning • Consider two waves traveling in opposite directions • Equal in amplitude • Equal in wavelength and frequency
Temporal and spatial components decoupled • At certain points, wave vanishes for all times • At other points, wave oscillates up and down • Wave does not appear to move – hence name
Nodes are places where amplitude is always zero • Antinodes are places where amplitude is a maximum
Making standing waves • Recall that when a wave hits a reflecting surface, it bounces back with the amplitude reversed. • This can generate a standing wave • Reflecting surfaces must be at nodes if wave medium is fixed to surface • Must be at anti-nodes if medium is not fixed.
Harmonics • All standing waves are multiples of half wavelengths • Simplest standing wave is ½ wavelength • Called fundamental frequency • Harmonics are multiples of fundamental frequency