Parallel electromagnetic waves with a common point of origin, the same frequency and phase, and propagating through the same medium, form an advancing wavefront perpendicular to their direction of travel.
- Point sources emitting light in all directions produce spherical wavefronts.
- Lasers that form a pencil of light made of parallel rays produce waves with flat wavefronts.
- An electromagnetic wave with a flat wavefront is called a plane wave.
Related diagrams
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