Two-Source Wave Interference
Two in-phase point sources emit circular waves — adjust the wavelength and their separation to see the exact bright/dark interference fringes form where the path lengths line up or cancel.
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What you can adjust
- Wavelength (λ)
- 0.02 – 0.5 m
- Source separation (d)
- 0.2 – 2 m
The distance between successive wave crests — through the path-length phase in the interference formula, a longer wavelength spreads the bright/dark fringes further apart.
Distance between the two in-phase point sources — a larger separation packs the interference fringes closer together on the screen.
About this simulation
What it shows
Two sources send out circular waves in step with each other. Where the waves meet they form a pattern of bright and dark bands that shows on a screen.
The key idea
Waves add. Where the two path lengths differ by a whole number of wavelengths the waves reinforce, and where they differ by half a wavelength they cancel. Longer waves or closer sources spread the bands further apart.
Try this
Increase Wavelength (λ) from 0.1 m to 0.2 m: the bright and dark bands spread further apart.