An electromagnetic wave is a phenomenon whereby an electric field and a magnetic field mutually interact and travel through space in the manner of a wave. Electromagnetic waves, expressed as frequency (i.e., the number of waves generated per second), are classified in order of descending frequency as radiation, light, and radio waves.
In places where electricity is flowing, electromagnetic waves are inevitably generated; for example, typical household electrical appliances generate electromagnetic waves with frequency of 50 to 60 Hz. Moreover, electrical devices like microwave ovens and mobile phones generate electromagnetic waves called "microwaves."
