Electricity is a general term that encompasses a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena such as lightning and static electricity, but in addition include less familiar concepts such as the electromagnetic field and electromagnetic induction.
In general usage, the word 'electricity' is adequate to refer to a number of physical effects. However, in scientific usage, the term is vague, and these related, but distinct, concepts are better identified by more precise terms:
- Electric charge – a property of some subatomic particles, which determines their electromagnetic interactions. Electrically charged matter is influenced by, and produces, electromagnetic fields.
- Electric current – a movement or flow of electrically charged particles, typically measured in amperes.
- Electric field – an influence produced by an electric charge on other charges in its vicinity.
- Electric potential – the capacity of an electric field to do work, typically measured in volts.
- Electromagnetism – a fundamental interaction between the electric field and the presence and motion of electric charge.
Electricity has been studied since antiquity, though scientific advances were not forthcoming until the 17th and 18th centuries. It would not be until the late 19th century, however, that engineers were able to put electricity to industrial and residential use. This period witnessed a rapid expansion in the development of electrical technology. Electricity's extraordinary versatility as a source of energy means it can be put to an almost limitless set of applications which include transport, heating, lighting, communications, and computation. The backbone of modern industrial society is, and for the foreseeable future can be expected to remain, the use of electrical power.
In physics, magnetism is one of the phenomena by which materials exert attractive or repulsive forces on other materials. Some well-known materials that exhibit easily detectable magnetic properties (called magnets) are nickel, iron, cobalt, and their alloys; however, all materials are influenced to greater or lesser degree by the presence of a magnetic field. Magnetism also has other manifestations in physics, particularly as one of the two components of electromagnetic waves such as light.
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