It has been suggested that this article or section be merged into Electrostatic force. (Discuss) In physics, Coulomb's law is an inverse-square law indicating the magnitude and direction of electrical force that one stationary, electrically charged object of small dimensions (ideally, a point source) exerts on another. Wikipedia does not have an article with this exact name. ...
In physics, the electrostatic force is the force arising between static (that is, non-moving) electric charges. ...
Since antiquity, people have tried to understand the behavior of matter: why unsupported objects drop to the ground, why different materials have different properties, and so forth. ...
Portrait of Coulomb Charles Augustin Coulomb (June 14, 1736 – August 23, 1806) was a French physicist. ...
This diagram shows how the law works. ...
In physics, a net force acting on a body causes that body to accelerate; that is, to change its velocity. ...
A point source may be a source of light that is treated as having no physical extension, or a source in fluid flow, or in electrostatics, or a source of pollution coming from a single cause, such as a municipal plant. ...
Coulomb's Law may be stated as follows:
"The magnitude of the electrostatic force between two point charges is directly proportional to the magnitudes of each charge and inversely proportional to the square of the distance between the charges."
When one is interested only in the magnitude of the force (and not in its direction), it may be easiest to consider a simplified, scalar version of the law Scalar is a concept that has meaning in mathematics, physics, and computing. ...
where (in SI units): The International System of Units (abbreviated SI from the French phrase, Système International dUnités) is the most widely used system of units. ...
is the magnitude of the force exerted, measured in newtons The newton (symbol: N) is the SI unit of force. ...
is the charge on one body, measured in coulombs The coulomb (symbol: C) is the SI unit of electric charge. ...
is the charge on the other body, also measured in coulombs The coulomb (symbol: C) is the SI unit of electric charge. ...
is the distance between them measured in metres The metre, or meter, is the basic unit of length in the International System of Units (SI: Système International dUnités). ...
is the electrostatic constant or Coulomb force constant, often written as where is a physical constant, the permittivity of free space. ≈ 8 987 742 438 F−1·m or C−2·N·m2, and ≈ 8.854 × 10−12 F·m−1 or C2·N−1·m−2. In cgs units, the unit charge, esu of charge or statcoulomb, is defined so that this Coulomb force constant is 1. In science, a physical constant is a physical quantity whose numerical value does not change. ...
This article is in need of attention. ...
The farad (symbol: F) is the SI unit of capacitance. ...
The metre, or meter, is the basic unit of length in the International System of Units (SI: Système International dUnités). ...
The coulomb (symbol: C) is the SI unit of electric charge. ...
The newton (symbol: N) is the SI unit of force. ...
The metre, or meter, is the basic unit of length in the International System of Units (SI: Système International dUnités). ...
The farad (symbol: F) is the SI unit of capacitance. ...
The metre, or meter, is the basic unit of length in the International System of Units (SI: Système International dUnités). ...
The coulomb (symbol: C) is the SI unit of electric charge. ...
The newton (symbol: N) is the SI unit of force. ...
The metre, or meter, is the basic unit of length in the International System of Units (SI: Système International dUnités). ...
CGS is an acronym for centimetre-gram-second. ...
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. ...
Note that , where is the permeability of vacuum and is the speed of light. Permeability has several meanings: In electromagnetism, permeability is the degree of magnetisation of a material in response to a magnetic field. ...
Cherenkov effect in a swimming pool nuclear reactor. ...
This formula says that the magnitude of the force is directly proportional to the magnitude of the charges of each object and inversely proportional to the square of the distance between them. Because, when measured in units people commonly use (such as MKS), the Coulomb force constant, , is numerically much much larger than the universal gravitational constant , which means that for objects with charge that is of the order of a unit charge (C) and mass of the order of a unit mass (kg), that the electrostatic forces will be so much larger than the gravitational forces that the latter force can be ignored. This is not the case when Planck units are used and both charge and mass are of the order of the unit charge and unit mass. However, charged elementary particles have mass that is far less than the Planck mass while their charge is about the Planck charge so that, again, gravitational forces can be ignored. This article is about proportionality, the mathematical relation. ...
This diagram shows how the law works. ...
The International System of Units (symbol: SI) (for the French phrase Système International dUnités) is the most widely used system of units. ...
According to the law of universal gravitation, the attractive force between two bodies is proportional to the product of their masses and inversely proportional to the square of the distance between them. ...
In physics, Planck units are physical units of measurement originally proposed by Max Planck. ...
In particle physics, an elementary particle is a particle of which other, larger particles are composed. ...
The force acts on the line connecting the two charged objects. Charged objects of the same polarity repel each other along this line and charged objects of opposite polarity attact each other along this line connecting them.
For calculating the direction and magnitude of the force simultaneously, one will wish to consult the full-blown vector version of the Law In physics and engineering, a vector is a physical entity which has a magnitude which is a scalar (a physical quantity expressed as the product of a numerical value and a physical unit, not just a number). ...
where
is the electrostatic force vector,
is the vector between the two charges, such that
where
is vector indicating the position of the charge on which the force acts
is the vector indicating the position of the other charge.
This vector equation indicates that opposite charges attract, and like charges repel. When is negative, the force is attractive. When positive, the force is repulsive. has been raised to the third power instead of the second in the denominator in order to normalize the length of the vector in the numerator to 1.
Below is a graphical representation of Coulomb's law. is the force experienced by . is the vector between two charges ( and ).
 A graphical representation of Coulomb's law. In either formulation, Coulomb's law is fully accurate only when the objects are stationary, and remains approximately correct only for slow movement. When movement takes place, magnetic fields are produced that alter the force on the two objects. The force resulting from magnetic field between moving charges can be thought of as a manifestation of the force from the electrostatic field but with Einstein's theory of relativity taken into consideration. Coulombs Law File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...
Current flowing through a wire produces a magnetic field (M) around the wire. ...
For other topics related to Einstein see Einstein (disambiguation). ...
Wikisource has original text related to this article: Relativity: The Special and General Theory Albert Einsteins theory of relativity is a set of two scientific theories in physics: special relativity and general relativity. ...
See also Electrostatics is the branch of physics that deals with the force exerted by a static (i. ...
In science, a physical constant is a physical quantity whose numerical value does not change. ...
References - Griffiths, David J. (1998). Introduction to Electrodynamics (3rd ed.). Prentice Hall. ISBN 013805326X.
- Tipler, Paul (2004). Physics for Scientists and Engineers: Electricity, Magnetism, Light, and Elementary Modern Physics (5th ed.). W. H. Freeman. ISBN 0716708108.
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