What is EMF ?
What are electromagnetic fields (EMFs)? What are electromagnetic waves?
The electromagnetic fields are a term for combining electric and magnetic fields. Electric voltage generates an electric field; electricity flowing generates a magnetic field.
Invisible EMF exist in many places around people. Home electric appliances, power equipment, and any other equipment that uses electricity generate EMF. TVs, radios, and mobile phones use EMF (radio waves) for telecommunications.
Electromagnetic radiation has been around since the birth of the universe; light is its most familiar form. Electric and magnetic fields are part of the spectrum of electromagnetic radiation which extends from static electric and magnetic fields, through radiofrequency and infrared radiation, to X-rays.
EMF also exists in nature. An electric field arises when a thundercloud is formed in the air. Static electricity is a phenomenon generated by an electric field. A magnetic field exists around a magnet. Compasses indicate north because of a magnetic field of the Earth (geomagnetism). Birds and fish find directions by the Earth magnetic field.
The electromagnetic waves describe the propagation of the electromagnetic fields.
An EMF generated from a transmission line or home electric appliance may be called an electromagnetic wave. However, since the wavelength of the commonly used EMF ranges from 5,000 to 6,000 km, the wave property can almost be disregarded in ordinary living space. Accordingly, it is more appropriate from a physics viewpoint that such an EMF be called an electromagnetic field rather than an electromagnetic wave.