Single-Slit Diffraction

Narrower openings spread light wider

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Single slit: first dark fringe at $\sin\theta = \lambda/a$.
• Narrower openings spread waves wider.
• Diffraction matters when openings are comparable to the wavelength.

Steps

1. Waves spread
2. Size the central spot
3. Sound round corners
4. Narrower slit
5. The central spot
6. The pupil’s limit