Electromagnetic fields can be both natural and made by humans . Natural electromagnetic fields are present in the Earth. While they may be invisible, electrical fields are based on the build-up of electric charges in the environment.
Read moreHow can we produce an electromagnetic field?
An electric field can be produced also by a changing magnetic field. The mutual interaction of electric and magnetic fields produces an electromagnetic field, which is considered as having its own existence in space apart from the charges or currents (a stream of moving charges) with which it may be related.
Read more