- Amplitude, wavelength, frequency, relating velocity to frequency and wavelength.
- Transverse and longitudinal waves.
- Electromagnetic waves, velocity in vacuum; waves transferring energy; wavelengths and frequencies from radio to gamma-rays.
- Velocities differing between media: absorption, reflection, refraction effects.
- Production and detection, by electrical circuits, or by changes in atoms and nuclei.
- Uses in the radio, microwave, infra-red, visible, ultra-violet, X-ray and gamma-ray regions, hazardous effects on bodily tissues.