Electromagnetism is the science of charge and of the forces and fields associated with charge. Electromagnetism consists of two aspects; electricity and magnetism. Until the 19th century, when they were treated as interrelated phenomena, they were long thought to be separate forces. In 1905, Albert Einstein’s special theory of relativity established beyond a doubt that both are aspects of one common phenomenon. However, electric and magnetic forces behave quite differently and are described by different equations. Electric forces are made by electric charges either at rest or in motion. Magnetic forces are made only by moving charges and act solely on charges in motion.
Electric phenomena occur even in the neutral matter because the forces act on the individual charged components. The electric force in particular is responsible for a majority of the physical and chemical properties of atoms and molecules. It is massively strong in comparison to gravity. For example, the absence of only one electron out of every billion molecules in two 70-kilogram people standing two meters apart would repeal them with a 30,000-ton-force. In more familiar terms, electric phenomena are responsible for lightning and thunder during certain storms.
Electric and magnetic forces can be verified in regions called electric and magnetic fields. These fields are fundamental in nature and can exist in space far from the charge or current that generated them. Electric fields can produce magnetic fields and so can the other way around, independent of any external charges. A changing magnetic field produces an electric field, as Michael Faraday, an English physicist, discovered in work that forms the basis of electric power generation. In opposition, a changing electric field produces a magnetic field as James Clerk Maxwell, a Scottish physicist, deduced. The mathematical equations formed by Maxwell incorporated light and wave phenomenon into electromagnetism. He showed that electric and magnetic fields travel together through space as waves of electromagnetic radiation, with the changing fields mutually sustaining each other.
Some examples of electromagnetic waves traveling through space independent of matter are radio and television waves, microwaves, infrared waves, visible light, ultraviolet light, X-rays, and gamma rays. All of these waves travel at the same speed-namely, the velocity of light (roughly 300,000 kilometers per second). They differ from each other only in the frequency at which their electric and magnetic fields oscillate. Maxwell’s equations still provide a complete description of electromagnetism down to the subatomic scale, but not including the subatomic scale. The interpretation of his work, however, was broadened in the 20th century. Einstein’s special relativity theory merged electric and magnetic fields into one common field and limited the velocity of all matter to the velocity of electromagnetic radiation.
In conclusion, electromagnetism is the science of charge consisting of electricity and magnetism. Until Albert Einstein’s further discovery they were thought to be separate forces, but then were treated as an interrelated phenomenon. Electric phenomena occur even in the neutral matter because the forces act on the individual charged components. The electric force in particular is responsible for a majority of the physical and chemical properties of atoms and molecules. Electric and magnetic forces can be verified in regions called electric and magnetic fields. These fields are fundamental in nature and can exist in space far from the charge or current that generated them. Some examples of electromagnetic waves traveling through space independent of matter are radio and television waves, microwaves, infrared waves, visible light, ultraviolet light, X-rays, and gamma rays.
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By: Zubin Sidhu
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References: McGrayne, Sharon Bertsch. “Electromagnetism.” Britannica, www.britannica.com/science/electromagnetism. Accessed 25 Apr. 2021.
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