What this simulator shows
Each colored band represents the combined intensity from two coherent sources. Points where the path difference is an integer multiple of the wavelength become bright fringes. Points where the path difference is a half-integer multiple become dark fringes.
📖 The physics behind the pattern
The simulator calculates the distance from every point on the screen to each source. Those distances set the local phase of each wave. The two amplitudes are added, then squared to estimate intensity, so the fringe map responds immediately when you change wavelength or phase offset.
Key relation
For two coherent sources, bright fringes occur when the path difference satisfies Δr = nλ, while dark fringes occur when Δr = (n + 1/2)λ.
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Pair the visual pattern with diffraction, refraction, and wave-speed formulas so the pattern has mathematical context.
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