The Environment of Space Chapter 6.
All electromagnetic waves propagate at the speed of light.
The wavelength of a single oscillation of electromagnetic radiation means the distance the wave will propagate during the time required for one oscillation. There is a simple relationship between the frequency of oscillation and wavelength of electromagnetic energy. Electromagnetic energy can be viewed in physics as if it were waves, as described above, and also as particles, known photons . It is generally common to speak of waves when talking about lower frequencies and longer wavelengths, such as radio waves. Reference to photons is common for physicists talking about light and EMF of higher frequencies.