PhysicsChapter 4: Diffraction and Interference
Diffraction of Waves and Single-Slit Diffraction
Diffraction
Definition
Diffraction is the spreading or bending of waves as they pass through an opening or around an obstacle, especially when the opening or obstacle size is comparable to the wavelength.
Effect of Wavelength
Diffraction is a fundamental wave property. It occurs for: sound, water waves, light, microwaves, and other waves. Diffraction becomes more noticeable when: **aperture size ≈ wavelength** If an opening is much larger than wavelength, spreading is relatively small.
Single-Slit Light Diffraction
When monochromatic light passes through a narrow slit of width: **a** different parts of the slit act as secondary wave sources. Their waves interfere. For minima: **a sinθ = mλ** where: `m = 1,2,3,...` The central maximum is usually the brightest and widest.
Formula / Key Relation
Single-slit minima: **a sinθ=mλ**
Exam preparation
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Review the key facts, formulas and checks before you move on.Diffraction of Waves and Single-Slit Diffraction
Sticky Notes · Quick Revision
Diffraction:
- wave spreading
- Strong when:
- `aperture ≈ λ`
- Single slit minima:
- `a sinθ=mλ`
60-second revision
- Diffraction is strong when obstacle/opening dimensions are comparable with wavelength.
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