Electric charge

Electromagnetism
Electricity · Magnetism · Magnetic permeability
Electrostatics Electric charge • Coulomb's law • Electric field • Electric flux • Gauss's law • Electric potential energy • Electric potential • Electrostatic induction • Electric dipole moment • Polarization density
Magnetostatics Ampère's law • Electric current • Magnetic field • Magnetization • Magnetic flux • Biot–Savart law • Magnetic dipole moment • Gauss's law for magnetism
Electrodynamics Lorentz force law • emf • Electromagnetic induction • Faraday’s law • Lenz's law • Displacement current • Maxwell's equations • EM field • Electromagnetic radiation • Liénard–Wiechert potential • Maxwell tensor • Eddy current
Electrical Network Electrical conduction • Electrical resistance • Capacitance • Inductance • Impedance • Resonant cavities • Waveguides
Covariant formulation Electromagnetic tensor • EM Stress-energy tensor • Four-current • Electromagnetic four-potential
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Electric charge is a basic property of electrons, protons and other subatomic particles. Electrons are negatively charged while protons are positively charged. Things that are negatively charged and things that are positively charged pull on (attract) each other. This makes electrons and protons stick together to form atoms. Things that have the same charge push each other away (they repel each other). This is called the Law of Charges. It was discovered by Charles-Augustin de Coulomb. The law that describes how strongly charges pull and push on each other is called Coulomb's Law.^[1]

Things that have equal numbers of electrons and protons are neutral. Things that have more electrons than protons are negatively charged, while things with fewer electrons than protons are positively charged. Things with the same charge repel each other. Things that have different charges attract each other. If possible, the one with too many electrons will give enough electrons to match the number of protons in the one that has too many protons for its load of electrons. If there are just enough electrons to match the extra protons, then the two things will not attract each other anymore. When electrons move from a place where there are too many to a place where there are too few, that is called an electrical current.

When a person shuffles their feet on a carpet and then touches a brass doorknob, they may get an electrical shock. If there are enough extra electrons then the force with which those electrons push each other away may be enough to make some of the electrons jump across a gap between the person and the doorknob. The length of the spark is a measure of voltage or "electrical pressure." The number of electrons that move from one place to another per unit of time measured as amperage or "rate of electron flow."

If a person gets a positive or negative charge, it may make the person's hairs stand up because the charges in each hair push it away from the others.

Electric charge felt when one gets a shock from a doorknob or other object usually is between 25 thousand and 30 thousand volts. However, the electric current only flows briefly, so the flow of electrons through the person's body does not cause physical harm. On the other hand, when clouds gain electrical charges they have even higher voltages and the amperage (the number of electrons that will flow in the lightning strike) can be very high. That means that electrons can jump from a cloud to the earth (or from the earth to a cloud). If those electrons go through a person, then the electric shock can burn or kill.

1. ↑ Purcell, Edward M. & David J. Morin 2013. Electricity and Magnetism. 3rd ed, Cambridge University Press. ISBN 978-1-107-01402-2