| English | Wave-particle duality |
|---|---|
| Bahasa Melayu | Kedualan gelombang-zarah |
| 中文 | 波粒二象性 |
Definition
The concept that light and matter can show both wave-like and particle-like properties depending on how they are observed.
In exam terms
Wave-particle duality means light and matter each behave in two ways depending on the experiment. Light behaves as a wave in diffraction and interference, yet behaves as a stream of particles called photons in the photoelectric effect.
A photon carries energy given by E = hf, where h is Planck's constant (about 6.63 × 10⁻³⁴ J s) and f is the frequency in Hz; energy is in joules (J).
Example of correct use: "Interference of light shows its wave nature, while the emission of photoelectrons shows its particle nature, so light displays wave-particle duality." It is a concept, not a quantity, so it has no unit or symbol of its own.
Do not confuse it with…
Do not confuse wave-particle duality (the whole idea that one thing shows both behaviours) with the photoelectric effect, which is only one experiment demonstrating the particle side. Duality is broader: it also covers the wave nature of light and the wave nature of moving matter.
In Paper 2, this is usually asked as a state or explain item, for example "State what is meant by wave-particle duality" or "Explain how two phenomena together show wave-particle duality." A full answer names one wave phenomenon (diffraction or interference) and one particle phenomenon (photoelectric effect) as evidence.
Source: DSKP KSSM Physics Form 4 and 5 (Versi English) (Bahagian Pembangunan Kurikulum (BPK), KPM)