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Wave Interference
Class XII · Wave Optics: Young’s double-slit, live amplitude field.
Controls
Separation d80 px
Wavelength λ30 px
Phase φ0.00 rad
Live readouts
D (slits → screen)324 px
d80 px
λ30 px
β = λD/d121.50 px
Formula
Path difference: Δ = d sinθ ≈ d x/D Bright: Δ = n λ (n = 0, ±1, …) Dark: Δ = (n+½) λ Fringe width: β = λD/d I(x) = 4 I₀ cos²(Δφ/2)
Try this: Halve d: fringes widen (β ∝ 1/d). Double λ: fringes also widen (β ∝ λ). Uncheck “in phase” — the central maximum becomes a dark band: that’s a π phase shift.