How Does Electromagnetic Force Work?

Moving electric charges produce magnetic fields.

The physical laws governing electromagnetic forces come from the related properties of electricity and magnetism. Changes in electric forces create magnetism, and changes in magnetic forces create electric currents. Light, chemistry, and electric power all depend on electromagnetic forces.

Charges

Electric charges are at the heart of all electromagnetic phenomena. Charges come in two kinds, positive and negative. The smallest charges are held by electrons, which are negative, and protons, which are positive. Opposite charges attract each other; like charges repel.

Faraday's Law

Faraday's law states that a changing magnetic field will produce an electric current in a wire. When a magnetic field moves, it in turn moves loosely-bound electrons in the wire's metal. The opposite is also true: When an electron moves, it produces a magnetic force.

Distance

The forces produced by electric charges and magnets both decrease with increasing distance although magnetic forces decrease faster. Electric attraction and repulsion vary as the inverse of the square of the distance between two charges. Magnetic forces vary as the inverse of the cube of the distance between magnets.

References

• Georgia State University: Faraday's Law
• Blaze Labs: "The Inverse Cube Law for Dipoles;" Xavier Borg; January 2009