Superposition
When waves meet, their displacements add. After meeting they carry on unchanged.
Last updated
Analogy
Two ripples crossing on a pond pass through each other.
Example
In step: 3 + 3 = 6 cmOpposite: 3 + (-3) = 0 cm
In practice
Two waves of height 3 cm in step make a 6 cm wave. Out of step by half a cycle, they cancel.
Practice
Flashcards
- What does destructive interference mean?Waves meet out of step and partly or fully cancel.
Questions people ask
What is the difference between constructive and destructive interference?
Constructive interference happens when waves meet in step, so their displacements add to a bigger wave. Destructive interference happens when waves meet out of step, so they partly or completely cancel. Noise-cancelling headphones use destructive interference by playing the opposite wave.
What is path difference?
Path difference is how much farther one wave travelled than another to reach the same point. If it is a whole number of wavelengths, the waves arrive in step and add. If it is half a wavelength, 1.5 wavelengths and so on, they cancel.