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Sparks — Electrical breakdown of a medium that produces an ongoing plasma discharge, similar to the instant spark, resulting from a current flowing through normally nonconductive media such as air. Telluric currents — Extremely low frequency electric current that occurs naturally over large underground areas at or near the surface of the Earth.
The electric field was formally defined as the force exerted per unit charge, but the concept of potential allows for a more useful and equivalent definition: the electric field is the local gradient of the electric potential. Usually expressed in volts per metre, the vector direction of the field is the line of greatest slope of potential, and ...
The fact that the force (and hence the field) can be calculated by summing over all the contributions due to individual source particles is an example of the superposition principle. The electric field produced by a distribution of charges is given by the volume charge density ρ ( r ) {\displaystyle \rho (\mathbf {r} )} and can be obtained by ...
The feeling of an electric shock is caused by the stimulation of nerves as the current flows through the human body. The energy stored as static electricity on an object varies depending on the size of the object and its capacitance, the voltage to which it is charged, and the dielectric constant of the surrounding medium.
The electromagnetic force is responsible for many of the chemical and physical phenomena observed in daily life. The electrostatic attraction between atomic nuclei and their electrons holds atoms together. Electric forces also allow different atoms to combine into molecules, including the macromolecules such as proteins that form the basis of life.
Electrical torture has been used in war and by repressive regimes since the 1930s. [49] During the Algerian War electrical torture was used by French military forces. [50] Amnesty International published a statement that Russian military forces in Chechnya tortured local women with electric shocks by attaching wires onto their breasts. [51]
The gravitational and electromagnetic interactions produce long-range forces whose effects can be seen directly in everyday life. The strong and weak interactions produce forces at subatomic scales and govern nuclear interactions inside atoms. Some scientists hypothesize that a fifth force might exist, but these hypotheses remain speculative.
Electrical phenomena are commonplace and unusual events that can be observed which illuminate the principles of the physics of electricity and are explained by them. Electrical phenomena are a somewhat arbitrary subset of phenomena of electromagnetism in general.