Superposition of Waves
The superposition of two or more waves can result in interference of: peak-peaks, peak-troughs or trough-troughs. The interference can be: constructive, destructive or total destructive.
Constructive interference: When two waves interfere to make a wave with a larger displacement.
Deconstructive interference: When two waves interfere to make a wave with a reduced displacement.
Total destructive interference: Destructive interference in which the waves completely cancel each other out.
Phase difference: The amount by which one wave lags behind another, measured as an angle.
One complete wave is 360 degrees or 2Pie radians
- Two points with a phase difference of zero or a multiple of 360 are in phase.
- In practice two waves are usually in phase if they come from the same oscillator.
- Two points on a wave are in phase if they are both at the same point in the wave cycle.
- Two points in phase interfere constructively with each other.
- Points in phase have the same displacement and velocity.
Out of phase:
- Points with a phase difference of odd-number multiples of 180 or 1Pie radians are exactly out of phase.
- There will nearly always be a phase difference between waves.