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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 ]
The force of attraction or repulsion between two electrically charged particles, in addition to being directly proportional to the product of the electric charges, is inversely proportional to the square of the distance between them; this is known as Coulomb's law. The deviation of the exponent from 2 is less than one part in 10 15. [8]
To move q+ closer to Q+ (starting from =, where the potential energy=0, for convenience), we would have to apply an external force against the Coulomb field and positive work would be performed. Mathematically, using the definition of a conservative force , we know that we can relate this force to a potential energy gradient as:
where r is the distance between the point charges q and Q, and q and Q are the charges (not the absolute values of the charges—i.e., an electron would have a negative value of charge when placed in the formula). The following outline of proof states the derivation from the definition of electric potential energy and Coulomb's law to this formula.
The electric potential arising from a point charge, Q, at a distance, r, from the location of Q is observed to be =, where ε 0 is the permittivity of vacuum [4], V E is known as the Coulomb potential.
Continuous charge distribution. The volume charge density ρ is the amount of charge per unit volume (cube), surface charge density σ is amount per unit surface area (circle) with outward unit normal nĚ‚, d is the dipole moment between two point charges, the volume density of these is the polarization density P.
The field due to magnetic charges is obtained through Coulomb's law with magnetic instead of electric charges. If the magnetic pole distribution is known, then the magnetic pole model gives the exact distribution of the magnetic field intensity H both inside and outside the magnet. The surface charge distribution is uniform, if the magnet is ...
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.