coulomb

(redirected from Columb)
Also found in: Dictionary, Thesaurus, Encyclopedia.

SI units

 
the units of measurement generally accepted for all scientific and technical uses; together they make up the International System of Units. (See also metric system.) The abbreviation SI, from the French Système International d'Unités, is used in all languages. There are seven base SI units, defined by specified physical measurements, and two supplementary units. Units are derived for any other physical quantities by multiplication and division of the base and supplementary units. The derived units with special names are shown in the accompanying table.



SI is a coherent system. This means that units are always combined without conversion factors. The derived unit of velocity is the meter per second (m/s); the derived unit of volume is the cubic meter (m3). If you know that pressure is force per unit area, then you know that the SI unit of pressure (the pascal) is the unit of force divided by the unit of area and is therefore equal to 1 newton per square meter.

The metric prefixes can be attached to any unit in order to make a unit of a more convenient size. The symbol for the prefix is attached to the symbol for the unit, e.g., nanometer (nm) = 10−9 m. The units of mass are specified in terms of the gram, e.g., microgram (μg) = 10−9 kg.

Only one prefix is used with a unit; the use of units such as the millimicrometer is no longer acceptable. When a unit is raised to a power, the power applies to the prefix as well, e.g., a cubic millimeter (mm3) = 10−9 m3. When a prefix is used with a ratio unit, it should be in the numerator rather than in the denominator, e.g., kilometers/second (km/s) rather than meters/millisecond (m/ms). Only prefixes denoting powers of 103 are normally used. Hecto-, deka-, deci-, and centi- are usually attached only to the metric system units gram, meter, and liter.

Owing to the force of tradition, one noncoherent unit, the liter, equal to 10−3 m3, or 1 dm3, is generally accepted for use with SI. The internationally accepted abbreviation for liter is the letter l; however, this can be confused with the numeral 1, especially in typescript. For this reason, the capital letter L is also used as a symbol for liter. The lower case letter is generally used with prefixes, e.g., dl, ml, fl. The symbols for all other SI units begin with a capital letter if the unit is named after a person and with a lower case letter otherwise. The name of a unit is never capitalized.

Coulomb

(kū-lohm),
Charles A. de, French physicist, 1736-1806. See: coulomb.

cou·lomb (C, Q),

(kū-lom'),
The unit of electrical charge, equal to 3 × 109 electrostatic units; the quantity of electricity delivered by a current of 1 A in 1 s equal to 1/96,485 faraday.
[CA de Coulomb, Fr. physicist, 1736-1806]

coulomb

/cou·lomb/ (C) (koo´lom) the SI unit of electric charge, defined as the quantity of electric charge transferred across a surface by 1 ampere in 1 second.

coulomb (C)

[ko̅o̅′lōm]
Etymology: Charles A. de Coulomb, French physicist, 1736-1806
the SI unit of electricity equal to the quantity of charge transferred in 1 second across a conductor in which there is a constant current of 1 ampere, or 1 ampere-second.

cou·lomb

(C) (kū'lom)
The SI unit of electrical charge, equal to 3 × 109 electrostatic units; the quantity of electricity delivered by a current of 1 ampere in 1 sec; equal to 1/96,485 faraday; also used to measure radiation.
See also: roentgen
[CA de Coulomb, Fr. physicist, 1736-1806]

coulomb

1. the unit of electrical charge, defined as the quantity of electrical charge transferred by 1 ampere in 1 second. Symbol C.
2. the SI unit of exposure to radiation. 1 coulomb per kilogram = 3876 roentgen; abbreviated C/kg.
References in periodicals archive ?
Columb, who grew up in Fettercairn in Tallaght, South Dublin, stole to feed his habit and said there was a time he would not have thought twice about breaking into any premises.
Columb admitted behaving in a threatening and abusive manner likely to cause fear and alarm by struggling violently with Jessie last May.
The next morning, Mr Rogers became worried when Mr Columb went to the toilet and hadn't come out.
Barclays Plc (LSE: BARC) has announced a plan to close its St Columb Major branch before the end of the year.
Jonson McClumpha and Liam Knight from Plains Farm were joined on the victors' rostrum by Columb Henry of the SR Club in Silksworth.
Anthony, of St Columb Major, Cornwall, and his friend Ricky James set out on their BMXs to visit a friend in nearby Indian Queens on February 6 this year.
Australian owners' chief Nick Columb hits out at overseas riders in advance of the Melbourne Cup following Ray Cochrane's controversial winning ride in the Caulfield Cup on Taufan's Melody, which Columb described as "contemptuous"
Photo: The Sea Bird and the Sea Lion will cruise the Columb ia and Snake rivers this fall.
We are very pleased to provide Albion Financial Group with the predictable service guarantees they were looking for," said U4EA Chief Executive Officer Columb Harrington.
Columb Strack, senior analyst and head of the IHS Conflict Monitor, warned: "As the Islamic State loses ground around Mosul, there is a high risk of the group using chemical weapons to slow down and demoralise advancing enemy forces.
The band is made up of Jasraj Sahota and Columb Finn, both 23 and from Stoke, Coventry.