Wavelength measures a complete wave cycle, which is the distance from any point on a wave to the corresponding point on the next wave.
- While wavelength can be measured from any point on a wave, it is often simplest to measure from the peak of one wave to the peak of the next or from the bottom of one trough to the bottom of the next, ensuring the measurement covers the whole of the cycle.
- The wavelength of an electromagnetic wave is usually given in metres.
- The wavelength of visible light is typically measured in nanometres, with 1,000,000,000 nanometres making up a metre.
- Radio waves, visible light, and gamma waves for example, each have different ranges of wavelengths within the electromagnetic spectrum.