Double-Slit Interference Calculator
Compute fringe spacing Δy = λL/d for a double-slit experiment.
Input Data
Wavelength Nm
nm
Slit Separation Mm
mm
Screen Distance M
m
Results
Δy in mm.
5.5mm
Δy = λL/d.
0.0055m
λ at first order.
0.00000055m
sinθ = λ/d.
0.315128°
At a glance:Δy = λL/d; maxima at d·sinθ = mλ. Complements single-slit-diffraction and diffraction-grating.
Formula
Δy = λ·L / d.
$$\Delta y = \frac{\lambda L}{d}$$$$d\sin\theta = m\lambda \quad (m=0,1,2,\dots)$$How to Use
- Enter λ, slit separation and screen distance.
- The tool returns fringe spacing and angle.
Case Studies
λ=600 nm, d=0.5 mm, L=1
Δy ≈ 1.2 mm.
FAQ
Bright vs dark?
Bright fringes at d sinθ = mλ; dark at (m+½)λ.
Related Tools
References
Content review: Calculatorism Science Team. Results are for reference only; please refer to the relevant authorities for the official figures.