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Amplitude, y₀
● VERBATIM — examined word-for-wordThe magnitude of the maximum displacement of a particle from its equilibrium position. Never "height of the wave".
What this actually means
Amplitude belongs to the oscillation, not the picture: the largest displacement magnitude a particle reaches, measured from equilibrium.
'Height of the wave' fails twice. Crest-to-trough distance is 2y₀, and 'height' is not measured from equilibrium. If a graph gives you crest to trough, halve it.
On a snapshot, amplitude is the distance from the centre line to a crest, and in an ideal 1-D wave every particle shares the same y₀.
Prove it — watch it be true
- Drag the amplitude slider and watch crests rise from the centre line
- Note crest-to-trough is twice the amplitude
- Every bead peaks at the same height: shared y₀