Point charge

From Wikipedia, the free encyclopedia

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.

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.

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.

[edit] See also

• Test charge
• Charge (physics) (charge, generally, i.e. not limited to electric charge)
  • Mass (sometimes referred to as gravitational charge)
  • Electric charge
  • Weak isospin (charge associated with weak interaction)
  • Color charge

[edit] 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.