Coherent Sources and Fringe Formation

This simulation visualises the interference pattern created by two coherent light sources. By adjusting the path difference, students can observe how constructive and destructive interference produce alternating bright and dark fringes on a screen, illustrating the fundamentals of wave optics.

Controls include a slider for source separation (d) ranging from 1 to 10 wavelengths, a slider for screen distance (D) measured in wavelengths, and a selector for screen orientation (parallel, perpendicular, or circular). Switches allow the display of the individual sine waves, the path‑difference construction, and an intensity graph beside the screen.

Students learn the quantitative relationship between wavelength, source spacing, and screen distance that determines fringe spacing, and they can explore how changing geometry affects the interference pattern, reinforcing concepts of constructive and destructive interference in optics.