3.3.2.1
Coherent sources have the same frequency and a constant phase difference
Interference & Diffraction — AQA A-Level Physics
Key Definition
Coherence — Two wave sources are coherent when they have the same frequency and a constant phase difference.
- CoherenceTwo wave sources are coherent if they have the same frequency and a constant phase relationship. is required for a stable, observable interference pattern.
- A laser produces coherent, monochromatic light -- ideal for interference experiments.
- Two separate light bulbs are not coherent because their phase relationship changes randomly.
- Two speakers connected to the same signal generator are coherent sound sources.