PhysicsChapter 7: Quantum Physics
Wave-Particle Duality and De Broglie Waves
Wave-particle duality
Definition
Wave-particle duality is the quantum idea that entities such as light and matter can display both wave-like and particle-like behaviour depending on the experiment. Louis de Broglie proposed that moving matter has an associated wavelength.
Meaning
Light shows wave behaviour through: interference; diffraction. Light also shows particle behaviour through: photoelectric effect; Compton scattering. De Broglie extended wave-particle duality to matter. For a particle with momentum `p`: λ = hp For a non-relativistic particle: p=mv therefore: λ=hmv Larger momentum gives smaller wavelength. For microscopic particles such as electrons, de Broglie wavelengths can be experimentally significant. For everyday macroscopic objects, the wavelength is so tiny that wave behaviour is practically unobservable.
Evidence
Electron diffraction and electron double-slit experiments support matter-wave behaviour.
Formula / Key Relation
**λ=hp Non-relativistic: λ=h/mv**
Exam preparation
Exam Focus
Quick revision
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Review the key facts, formulas and checks before you move on.Wave-Particle Duality and De Broglie Waves
Sticky Notes · Quick Revision
Matter wave:
- `λ=hp`
- Small p → large λ
- Large p → small λ
60-second revision
- de Broglie connected particle momentum with wavelength.
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