- distance between consecutive peaks (or troughs) of a wave
- measured in meters; light wavelengths typically in nanometers (nm)
- determines color in the visible spectrum: ~380 nm (violet) to ~700 nm (red)
- determines pitch in sound: longer wavelength = lower frequency = deeper tone
- related to frequency by: wavelength = speed / frequency
- electromagnetic spectrum spans radio waves (km) to gamma rays (pm)
- de Broglie wavelength assigns a wavelength to particles with momentum
- diffraction and interference effects depend on the ratio of wavelength to obstacle size
- antenna length scales with the wavelength of the signal it transmits or receives