The electromagnetic field describes the basic attributes characterizing electromagnetic radiation
Pattern of lines of the electric field
Electric fields are formed around bodies carrying an electric charge. The greater the distance from the charge, the weaker the field. Friction between two bodies, for instance, creates electric charges on these bodies, generating electric fields around them. These electric fields attract dust, floating particles, etc. The electric field is measured in units of volts per meter (V/m).
Magnetic fields are created around an electric current (such as that flowing through high-voltage power lines). The stronger the current, the stronger the magnetic field created around it. The power of the field decreases as a square of the distance from the source of the electric current. Magnetic fields are also generated around magnetic bodies. For instance, if iron filings are scattered near a magnet, they will align themselves according to the field lines of the magnet. The magnetic field is measured in units of Amperes per meter (A/m) or millie gauss units (mG) or Tesla (T).
Pattern of lines of a magnetic field
Scattered iron filings near magnets illustrate the magnetic field lines