Electromagnetic waves are waves which can travel through the vacuum of outer space. The vibration of an electric charge generates electromagnetic waves. This vibration generates a wave with a part that is both electric and magnetic. At a speed of 3.00 x 108 m/s, an electromagnetic wave transfers its energy through a vacuum (a speed value commonly represented by the symbol c). The propagation of an electromagnetic wave occurs at a net speed through a material medium, which is less than 3.00 x 108 m/s. simplify to a shor sententence