In physics, the electrostatic force is the force arising between static (that is, nonmoving) electric charges. This force is proportional to the product of the electric charges, and inversely proportional to the distance between the charges. The magnitude of the force takes the form: Physics (from the Greek, φυσικός (phusikos), natural, and φύσις (phusis), nature) is the science of nature in the broadest sense. ...
Electric charge is a fundamental property of some subatomic particles, which determines their electromagnetic interactions. ...
This article is about proportionality, the mathematical relation. ...
where F is the magnitude of the force (in newtons), This article is about the SI unit of force. ...
ε_{0} is the permitivity of free space, q_{1} and q_{2} are the charge magnitudes (in coulombs), The coulomb, symbol C, is the SI unit of electric charge, and is defined in terms of the ampere: 1 coulomb is the amount of electric charge (quantity of electricity) carried by a current of 1 ampere flowing for 1 second. ...
and r is the distance between the two charges in metres. The direction of the force vector is along the axis joining the two charges, which can be expressed in the following vector equation: metre or meter, see meter (disambiguation) The metre is the basic unit of length in the International System of Units. ...
In physics and engineering, the word vector typically refers to a quantity that has close relationship to the spatial coordinates, informally described as an object with a magnitude and a direction. The word vector is also now used for more general concepts (see also vector and generalizations below), but this...

where is the electrostatic force vector, and is the vector between the two charges, such that where r_{1} is the charge on which the force acts, and r_{2} is the other charge. Note that when q_{1} and q_{2} are the same sign the force vector acts in the same direction as r  Like charges repel. When they are of opposite signs the force vector acts in the opposite direction to r  unlike charges attract. In the cgs system of measurement, the force coefficient is included in the unit definitions, giving the simpler equation: CGS is an acronym for centimetregramsecond. ...
where is the force vector (in dynes), In physics, the dyne is a unit of force specified in the centimetregramsecond (cgs) system of units, symbol dyn. One dyne is equal to exactly 105 newtons. ...
q_{1} and q_{2} are the charges (in statcoulombs), The statcoulomb (statC) or franklin (Fr) or electrostatic unit of charge (esu) is the physical unit for electrical charge used in the cgs electrostatic system of units. ...
and and r are the distance vector and magnitude, measured in centimetres. The above equation can also be interpreted in terms of atomic units with the force expressed in Hartrees per Bohr radius, the charge in terms of the elementary charge, and the distances in terms of the Bohr radius. cm redirects here, alternate uses: cm (disambiguation) A centimetre (symbol cm; American spelling: centimeter) is an SI unit of length. ...
Atomic units(au) are a convenient system of units of measurement used in atomic physics, particularly for describing the properties of electrons. ...
The Hartree energy (symbol Eh) is a physical constant used as atomic unit of energy, named after physicist Douglas Hartree. ...
This article may be too technical for most readers to understand. ...
The elementary charge (symbol e or sometimes q) is the electric charge carried by a single proton, or equivalently, the negative of the electric charge carried by a single electron. ...
