[P6.1]
is: a pattern of mutually perpendicular, oscillating electric and magnetic fields that can travel through a vacuum at the speed of light, [P6.1]
is a form: of transverse wave. [P6.1]
is characterized: in the simplest case (a linearly polarized, monochromatic, plane wave), by its direction of propagation, plane of polarization, amplitude, wavelength and frequency. (In a vacuum the wavelength and frequency are related by 
). [P6.1]
has speed: 
in materials other than a vacuum, where 
is the refractive index of the material. [P6.1]
Copyright 1997, The Open University