coulomb

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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]

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]
References in periodicals archive ?
For example, at CS of 40 MPa in all mixes of HPC, the CPC values are around 5266.8 coulombs for control mix and 1847 coulombs and 1854 coulombs for 30 and 50% GGBFS of HPC, respectively.
Figure 3 illustrates that the cement replacement with GGBFS in HPC (0.37% of w/b) had lesser coulomb values when compared to control mix.
The instrument is used in the charge (or coulombs) mode, and its internal voltage source provides the step voltage.
Turn on the electrometer, select the coulombs function, then disable "Zero Check" and press "Rel" to zero the display.
3 Unification of Newton's law of gravity and Coulomb's law
Considering two pointlike electrically charged objects with masses [M.sub.1], [M.sub.2], electric charges [Q.sub.1], [Q.sub.2], and distance r, we can unify Newton's law of gravity and Coulomb's law of electric force by the following single expression of the interaction between complex energies
The quality of the untreated removed deck section showed that the concrete had a low water-cement ratio and a low chloride permeability with a value of about 2,000 coulombs. None of the sealer-treated disk samples achieved the very low permeability level of 100 to 1,000 coulombs as observed for latex-modified and internally sealed concretes.
For the POFA concrete, the values of total passed charges for the 50P15, 50P25, and 50P35 types of concrete were 2140, 1459, and 1151 coulombs at 28 days and declined to 1012, 890, and 830 coulombs at 90 days, respectively.
The types of concrete with the same replacement of ground POFA, that is, the 25% replacement of OPC in the 40P25 and 50P25 types of concrete at 90 days, had the total passed charges of 661 and 890 coulombs, respectively.
This article aims to show that Nagaoka's model of the atom (3) and Rutherford's (4) are identical in view of their Coulomb potential related to the atomic nucleus.
Data on differences in spectra associated with different isotopes of heavy elements is being accumulated rapidly at present and may in the future prove an important source of knowledge about the nucleus, but at present not much more can be said than that reasonable assumed departures from the Coulomb law in the neighbourhood of the nucleus can account in order of magnitude for the observed effects.