Enter Simulation Inputs
Example Data Table
This example shows a symmetric interference pattern for equal sources.
| Position x (mm) | Path Difference (µm) | Phase (rad) | Intensity |
|---|---|---|---|
| -2.0 | -0.833 | -9.516 | 3.972 |
| -1.0 | -0.417 | -4.758 | 0.004 |
| 0.0 | 0.000 | 0.000 | 4.000 |
| 1.0 | 0.417 | 4.758 | 0.004 |
| 2.0 | 0.833 | 9.516 | 3.972 |
Formula Used
Distance from source 1: r1 = √[(x + d/2)2 + L2]
Distance from source 2: r2 = √[(x - d/2)2 + L2]
Path difference: Δr = r2 - r1
Total phase difference: φ = (2π/λ)Δr + φ0
Resultant amplitude: A = 2a cos(φ/2)
Intensity for equal sources: I = 4I0 cos2(φ/2)
The graph plots screen position against calculated intensity.
How to Use This Calculator
- Enter the wavelength in nanometers.
- Provide source spacing in millimeters.
- Set the distance from sources to screen.
- Enter any initial phase offset in degrees.
- Choose base intensity and source amplitude values.
- Select the screen range you want to inspect.
- Set the number of sample points.
- Click Run Simulation to generate results.
- Review summary values, graph, and data table.
- Export the calculated dataset as CSV or PDF.
Frequently Asked Questions
1. What does this calculator simulate?
It simulates interference from two coherent wave sources. It calculates path difference, total phase, resultant amplitude, and intensity across selected screen positions.
2. What causes bright and dark fringes?
Bright fringes appear when waves arrive mostly in phase. Dark fringes appear when waves arrive mostly out of phase, causing destructive interference.
3. Why does wavelength affect fringe spacing?
Larger wavelengths produce wider fringe spacing for fixed geometry. Smaller wavelengths compress the fringe pattern because phase changes faster across the screen.
4. How does source spacing change the pattern?
Increasing source spacing usually reduces fringe spacing. The fringes become closer because the path difference changes more quickly with position.
5. What is the role of phase offset?
Phase offset shifts the interference pattern left or right in phase terms. It changes where constructive and destructive regions occur.
6. Can this model represent light and sound?
Yes. The mathematics suits any coherent wave pair when geometry and phase behavior match the assumptions used in the calculation.
7. Why are equal source formulas used?
This page uses the standard equal-source intensity relation for clarity. It gives a clean interference pattern and works well for many learning cases.
8. What do CSV and PDF exports contain?
CSV export saves the full numeric dataset. PDF export includes key summary values and a reduced table preview for easy reporting.