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Ampere

The ampere (SI unit symbol: A), often shortened to amp, is the SI unit of electric current[1] (quantity symbol: I,i)[2] and is one of the seven[3] SI base units. It is named after André-Marie Ampère (1775–1836), French mathematician and physicist, considered the father of electrodynamics. Note that SI supports only the use of symbols and deprecates the use of any abbreviations for units.[4]

Volt From Wikipedia, the free encyclopedia Jump to: navigation, search For other uses, see Volt (disambiguation). Josephson junction array chip developed by NIST as a standard volt The volt (symbol: V) is the SI derived unit for electric potential, electric potential difference, and electromotive force.[1] The volt is named in honor of the Italian physicist Alessandro Volta (1745–1827), who invented the voltaic pile, possibly the first chemical battery.

A single volt is defined as the difference in electric potential across a wire when an electric current of one ampere dissipates one watt of power.[

Coulomb

The coulomb (symbol: C) is the SI derived unit of electric charge. It is defined as the charge transported by a steady current of one ampere in one second: One coulomb is also the amount of excess charge on the positive side of a capacitance of one farad charged to a potential difference of one volt:

A particle carrying a charge of 1 coulomb and passing through a magnetic field of 1 tesla at a speed of 1 meter per second perpendicular to said field experiences a force of 1 newton, according to the Lorentz force law. As an SI derived unit, the tesla can also be expressed as (in SI base units).[3] Units used: A = ampere C = coulomb kg = kilogram m = meter N = newton s = second T = tesla V = volt Wb = weber [edit] Electric vs Magnetic Field

The difference between magnetic field strength (in tesla) vs electric field strength can be confusing.[citation needed] The difference is that a force of magnetic field on a charged particle is generally due to the charged particle's movement[4] while the force imparted by an electric field on a charged particle is not due to the charged particle's movement. This can be seen by looking at the units for each. Electric field is N/C, while magnetic field (in tesla) can be written as N/(C*m/s). The difference between the two is m/s, or velocity. This can further be seen by noting that whether a field is magnetic or electric is dependent on one's relativistic reference frame (that is: one's velocity relative to the field).[5][6] In ferromagnets the movement creating the magnetic field is the electron spin[7] (and to a lesser extent electron orbital angular momentum). In current carrying wire (electromagnets) the movement is due to electrons moving through the wire (whether the wire's straight or circular).

Weber (unit) From Wikipedia, the free encyclopedia Jump to: navigation, search In physics, the weber (symbol: Wb;  /ˈveɪbər/, /ˈwɛbər/, or /ˈwiːbər/) is the SI unit of magnetic flux. A flux density of one Wb/m2 (one weber per square meter) is one tesla. The weber is named for the German physicist Wilhelm Eduard Weber (1804–1891). [edit] Definition

The weber may be defined in terms of Faraday's law, which relates a changing magnetic flux through a loop to the electric field around the loop. A change in flux of one weber per second will induce an electromotive force of one volt (produce an electric potential difference of one volt across two open-circuited terminals). Officially,

Weber (unit of magnetic flux) — The weber is the magnetic flux which, linking a circuit of one turn, would produce in it an electromotive force of 1 volt if it were reduced to zero at a uniform rate in 1 second.[1]