What are the properties of electromagnetic waves?

EM waves invariantly travel at the speed of light, and can do so in a vacuum. They transfer energy from their source to the absorber. Some kinds of EM waves can be reflected and refracted. The spectrum of electromagnetic radiation includes waves with low frequency and energy and long wavelength (e.g. radio waves) all the way to waves with high frequency and energy and short wavelength (e.g. gamma rays).