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Coulomb's inverse-square law, or simply Coulomb's law, is an experimental law [1] of physics that calculates the amount of force between two electrically charged particles at rest. This electric force is conventionally called the electrostatic force or Coulomb force . [ 2 ]
Coulomb also experimentally determined the law that explains how "two bodies electrified of the same kind of Electricity exert on each other." On page 574 he states: Il résulte donc de ces trois essais, que l'action répulsive que les deux balles électrifées de la même nature d'électricité exercent l'une sur l'autre, suit la raison ...
The coulomb was originally defined, using the latter definition of the ampere, as 1 A × 1 s. [4] The 2019 redefinition of the ampere and other SI base units fixed the numerical value of the elementary charge when expressed in coulombs and therefore fixed the value of the coulomb when expressed as a multiple of the fundamental charge.
Coulomb's law and Newton's law of universal gravitation are based on action at a distance. Historically, action at a distance was the earliest scientific model for gravity and electricity and it continues to be useful in many practical cases. In the 19th and 20th centuries, field models arose to explain these phenomena with more precision.
When talking about electrostatic potential energy, time-invariant electric fields are always assumed so, in this case, the electric field is conservative and Coulomb's law can be used. Using Coulomb's law, it is known that the electrostatic force F and the electric field E created by a discrete point charge Q are radially directed from Q.
It is defined as the electrostatic force , on a hypothetical small test charge at the point due to Coulomb's law, divided by the charge = Electric field lines are useful for visualizing the electric field. Field lines begin on positive charge and terminate on negative charge.
Performing dimensional analysis on Coulomb's law, the dimension of electrical charge in CGS must be [mass] 1/2 [length] 3/2 [time] −1. (This statement is not true in the International System of Quantities upon which the SI is based; see below.) We can be more specific in light of the definition above: Substituting F = 1 dyn, q G 1 = q G
Similarly, the Newtonian gravitation law is a low-mass approximation of general relativity, and Coulomb's law is an approximation to quantum electrodynamics at large distances (compared to the range of weak interactions). In such cases it is common to use the simpler, approximate versions of the laws, instead of the more accurate general laws.