Young’s Double Slit Calculator
🔍 Light & optics. Use the Young’s double slit formula to find fringe spacing, wavelength λ, distance to the screen, slit separation: pick the value you want, type the others, and the answer updates as you go.
w = fringe spacing, D = slits to screen, s = slit separation.
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| Fringe spacing | m |
| Wavelength λ | m |
| Distance to the screen | m |
| Slit separation | m |
Worked example
Find the fringe spacing when Wavelength λ = 6 × 10⁻⁷ m, Distance to the screen = 5 m, Slit separation = 5 × 10⁻⁴ m.
Using w = (λ D)/s: Fringe spacing = 0.006 m.
Frequently asked questions
What is the formula for Young’s double slit?
w = (λ D)/s. w = fringe spacing, D = slits to screen, s = slit separation.
What do the letters stand for, and what units are used?
Fringe spacing in m, Wavelength λ in m, Distance to the screen in m, Slit separation in m.
How do you calculate fringe spacing?
Put the values into w = (λ D)/s. For example, with Wavelength λ = 6 × 10⁻⁷ m, Distance to the screen = 5 m, Slit separation = 5 × 10⁻⁴ m, fringe spacing = 0.006 m.
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (fringe spacing, wavelength λ, distance to the screen, slit separation) and fill in the others: it rearranges the formula for you.
