Electromagnetic Fields

Electromagnetism is a branch of physics concerned with the study of electromagnetic force, one of the four primary forces in nature (the other three being the strong nuclear force, weak nuclear force, and gravity). It is a type of physical interaction that occurs between electrically charged particles. Electromagnetism is the major factor that determines the properties of most everyday objects.

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What is Electromagnetism?

Electromagnetism is a subfield of physics that studies the force that exists between electrically charged particles. It is also known as the electromagnetic force. The electromagnetic force is among the four known primary forces (strong nuclear force, weak nuclear force, gravitational force, and electromagnetic force). Electromagnetic force is carried by electromagnetic fields, which are composed of electric fields and magnetic fields, and it is responsible for electromagnetic radiation such as light, radio waves and x-rays.

Electromagnetic force is a key factor in determining the properties of most everyday objects. The electromagnetic attraction between negatively charged electrons and positively charged atomic nuclei is what holds atoms together. The same force governs all chemical processes, and is responsible for the chemical bonds between atoms that create molecules, as well as intermolecular forces. Electromagnetism also forms the basis of electronics and electric power engineering and is widely used in modern technology.

Electricity and magnetism were originally thought to be two separate forces, until James Clerk Maxwell published “A Treatise on Electricity and Magnetism” in 1873. Maxwell conclusively demonstrated that the interactions of positive and negative charges were shown to be mediated by a single, unified force, rather than two separate forces of electricity and magnetism.


The history of electromagnetism dates back to 1820 and a discovery made by Hans Christian Oersted. A battery was used to supply electric current to a compass and the needle drifted from the magnetic north every time the electric current was turned on and off. This experiment convinced Orsted that magnetic fields emanate from all sides of an electric current-carrying wire.

Michael Faraday, a researcher, and inventor was responsible for developing significant theories and innovations in the electromagnetic field. He was the first to discover electromagnetic induction and electrolysis. His finding of rotating electromagnetic devices resulted in the design of the electric motor. Faraday was also the first scientist to discover the connection between magnetism and light.

James Maxwell carried out a number of tests, culminating in his 1873 publication, that proved there was a link between electricity and magnetism. He discovered magnetic poles by observing the interplay of a wire's positive and negative electrical charges. Maxwell expanded on Faraday's findings and developed the system of equations that is now the foundation of all contemporary electromagnetic theories.

Use and Application

Electromagnetism and electromagnetic theory has many uses. Some examples include: 

  • All electronic devices, from motors to smartphones
  • Communication systems where electromagnetic radiation transports data from the sender to the receiver e.g. radio, television, microwave transmitters.
  • Maglev trains, often known as high-speed trains, operate on the electromagnetic principle.
  • Power generation systems.
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