A point charge is an idealized model of a particle which has an electric charge. A point charge is an electric charge at a mathematical point with no dimensions. This box:      Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. ... A spatial point is an entity with a location in space but no extent (volume, area or length). ...

The fundamental equation of electrostatics is Coulomb's law, which describes the electric force between two point charges. The electric field associated with a classical point charge increases to infinity as the distance from the point charge decreases towards zero making energy (thus mass) of point charge infinite. In quantum electrodynamics, developed in part by Richard Feynman, the mathematical method of renormalization eliminates the infinite divergence of the point charge. An equation is a mathematical statement, in symbols, that two things are the same (or equivalent). ... Electrostatics (also known as static electricity) is the branch of physics that deals with the phenomena arising from what seem to be stationary electric charges. ... Coulombs torsion balance In physics, Coulombs law is an inverse-square law indicating the magnitude and direction of electrostatic force that one stationary, electrically charged object of small dimensions (ideally, a point source) exerts on another. ... In physics, the space surrounding an electric charge or in the presence of a time-varying magnetic field has a property called an electric field. ... Quantum electrodynamics (QED) is a relativistic quantum field theory of electrodynamics. ... This article is about the physicist. ...

Earnshaw's theorem states that a collection of point charges cannot be maintained in an equilibrium configuration solely by the electrostatic interaction of the charges. Earnshaws theorem states that a collection of point charges cannot be maintained in a stable stationary equilibrium configuration solely by the electrostatic interaction of the charges. ... A standard definition of mechanical equilibrium is: A system is in mechanical equilibrium when the sum of the forces, and torque, on each particle of the system is zero. ...

See also

• Test charge

A test charge is an object (usually a point particle) that has negligible charge; one can ignore the electrical field generated by the object itself. ...

References

• Eric W. Weisstein, "Point Charge".
• F. H. J. Cornish, "Classical radiation theory and point charges". Proc. Phys. Soc. 86 427-442, 1965. doi:10.1088/0370-1328/86/3/301
• O. D. Jefimenko, "Direct calculation of the electric and magnetic fields of an electric point charge moving with constant velocity". Am. J. Phys.62 (1994), 79.