Coulomb

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Coulomb

The coulomb (symbol: C

C or c is a consonant in Esperanto orthography, representing a voiceless postalveolar affricate , and is equivalent to the voiceless postalveolar affricate, , or the voiceless retroflex affricate, ...
) is the SI

Si, si, or SI may refer to :...
unit of electric charge

Electric charge

Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. Electrically charged matter is influenced by, and produces, electromagnetic fields....
. It is named after Charles-Augustin de Coulomb.

coulomb is the amount of charge stored by a capacitance

Capacitance

In electromagnetism and electronics, capacitance is the ability of a body to hold an electrical charge.Capacitance is also a measure of the amount of electric charge stored for a given electric potential....
of one farad

Farad

The farad is the SI unit of capacitance. The farad is named after the British physicist Michael Faraday....
charged to a potential difference of one volt

Volt

The volt is the SI SI derived unit of electric potential difference or electromotive force, commonly known as voltage. It is named in honor of the Lombard physicist Alessandro Volta , who invented the voltaic pile, possibly the first chemical battery ....
:

Explanation
In principle, the coulomb could be defined in terms of the charge of an electron

Electron

Discussion

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Definition

One coulomb is the amount of electric charge transported in one second

Second

The second , sometimes abbreviated sec., is the name of a units of measurement of time, and is the International System of Units SI base unit of time....
by a steady current

Electric current

Electric current is the flow of electric charge. The electric charge may be either electrons or ions.The International System of Units unit of electric current intensity is the ampere....
of one ampere

Ampere

The ampere is the International System of Units unit of electric current. The ampere, in practice often shortened to amp, is an SI base unit, and is named after Andr?-Marie Amp?re, one of the main discoverers of electromagnetism....
.

One coulomb is the amount of charge stored by a capacitance

Capacitance

Farad

The farad is the SI unit of capacitance. The farad is named after the British physicist Michael Faraday....
charged to a potential difference of one volt

Volt

Explanation

In principle, the coulomb could be defined in terms of the charge of an electron

Electron

The electron is a subatomic particle that carries a negative electric charge. It has elementary particle and is believed to be a point particle....
or elementary charge
Elementary charge

The elementary charge, usually denoted e, is the electric charge carried by a single proton, or equivalently, the negative of the electric charge carried by a single electron....
. Since the values of the Josephson (CIPM (1988) Recommendation 1, PV 56; 19) and von Klitzing (CIPM (1988), Recommendation 2, PV 56; 20) constants have been given conventional values (K_J = 4.835 979 Hz/V and R_K = 2.581 280 7 O), it is possible to combine these values to form an alternative (not yet official) definition of the coulomb. A coulomb is then equal to exactly 6.241 509 629 152 65 elementary charges. Combined with the present definition of the ampere

Ampere

Kilogram

The kilogram or kilogrammeThe spelling kilogram is used by the International Committee for Weights and Measures and the U.S....
a derived unit.

In everyday situations, positive and negative charges are usually balanced out. According to Coulomb's Law

Coulomb's law

Coulomb's law, sometimes called the Coulomb law, is an equation describing the electrostatic force between electric charges. It was developed in the 1780s by French physicist Charles Augustin de Coulomb and was essential to the development of the classical electromagnetism....
, two point charge

Point charge

A point charge is an idealized model of a particle which has an electric charge. A point charge is an electric charge at a Point with no dimensions....
s of +1 C, one meter apart, would experience a repulsive force

Force

In physics, a force is that which can cause an object with mass to change its velocity. Force has both Euclidean_vector#Length of a vector and Direction , making it a Vector quantity....
of 9 N, roughly the equivalent of 900,000 metric tons of weight

Weight

In the physical sciences, weight is a measurement of the gravitational force acting on an object. Near the surface of the Earth, the Earth's gravity is approximately constant; this means that an object's weight is roughly proportional to its mass....
.

Historical note

The ampere
Ampere

The ampere is the International System of Units unit of electric current. The ampere, in practice often shortened to amp, is an SI base unit, and is named after Andr?-Marie Amp?re, one of the main discoverers of electromagnetism....
was historically a derived unit—being defined as 1 coulomb per second. Therefore the coulomb, rather than the ampere, was the SI base electrical unit.

In 1960 the SI made the ampere the base unit.

SI multiples

Conversions

The electrical charge of one mole
Mole (unit)

The mole is a Units of measurement of amount of substance: it is an SI base unit, and one of the few units used to measure this physical quantity....
of electrons (approximately 6.022 electrons, or Avogadro's number
Avogadro's number

The Avogadro constant , also called Avogadro's number, is the number of "elementary entities" in one mole , that is , the number of atoms in exactly 12 grams of carbon-12....
) is known as a faraday
Faraday constant

In physics and chemistry, the Faraday constant is the magnitude of electric charge per mole of electrons. While most uses of the Faraday constant, denoted F, have been replaced by the standard SI unit, the coulomb, the Faraday is still widely used in calculations in electrochemistry....
(actually –1 faraday, since electrons are negatively charged). One faraday equals 96485.3399 coulombs (the Faraday constant
Faraday constant

In physics and chemistry, the Faraday constant is the magnitude of electric charge per mole of electrons. While most uses of the Faraday constant, denoted F, have been replaced by the standard SI unit, the coulomb, the Faraday is still widely used in calculations in electrochemistry....
). In terms of Avogadro's number (N_A), one coulomb is equal to approximately 1.036 × N_A elementary charges.

one ampere-hour
Ampere-hour

An ampere-hour or amp-hour is a unit of electric charge, with sub-units milliampere-hour and milliampere second . One ampere-hour is equal to 3600 coulombs , the electric charge transferred by a steady current of one ampere for one hour....
= 3600 C

The elementary charge
Elementary charge

The elementary charge, usually denoted e, is the electric charge carried by a single proton, or equivalently, the negative of the electric charge carried by a single electron....
is 1.602176487 C

One statcoulomb
Statcoulomb

The statcoulomb or franklin or electrostatic unit of charge is the Units of measurement for electrical charge used in the centimetre gram second system of units electrostatic system of units....
(statC), the CGS electrostatic unit of charge (esu), is approximately 3.3356 C or about 1/3 nC.

One coulomb is the amount of electrical charge in 6.241506 electrons or other elementary charged particles.

Coulomb

Definition

Explanation

Historical note

SI multiples

Conversions

See also