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Topic: SI derived unit


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SI
Ohm

  
  Essentials of the SI: Base & derived units
Examples of such SI derived units are given in Table 2, where it should be noted that the symbol 1 for quantities of dimension 1 such as mass fraction is generally omitted.
In photometry, the unit name steradian and the unit symbol sr are usually retained in expressions for derived units.
For a graphical illustration of how the 22 derived units with special names and symbols given in Table 3 are related to the seven SI base units, see relationships among SI units.
physics.nist.gov /cuu/Units/units.html   (468 words)

  
  SI derived unit - Wikipedia, the free encyclopedia
SI derived units are part of the SI system of measurement units and are derived from the seven SI base units.
The unit of angle is the angle subtended at the centre of a circle by an arc of the circumference equal in length to the radius of the circle.
The unit of solid angle is the solid angle subtended at the centre of a sphere of radius r by a portion of the surface of the sphere having an area r
en.wikipedia.org /wiki/SI_derived_unit   (327 words)

  
 Siemens (unit) - Encyclopedia, History, Geography and Biography   (Site not responding. Last check: 2007-10-24)
The siemens (symbol: S) is the SI derived unit of electric conductance.
The term siemens, as it is an SI unit, is used universally in science and primarily in electrical applications, while mho is still used primarily in electronic applications.
The upside down ohm symbol, while not an official SI unit, has the advantage of being less likely to be confused with a variable than the letter S when doing algebraic calculations by hand, where the usual typographical distinctions (such as italic for variables and roman for unit names) are difficult to maintain.
www.arikah.net /encyclopedia/Mho   (305 words)

  
 Wikipedia: Katal
Katal is the SI derived unit for catalytic activity.
The name katal had been used for this unit for decades, but did not become an official SI derived unit until 1999 with Resolution 12 of the 21st CGPM, on the recommendation of the International Federation of Clinical Chemistry and Laboratory Medicine.
"Units" are more commonly used than the katal in practice at present, but their definition lacks coherence with the SI system.
www.factbook.org /wikipedia/en/k/ka/katal.html   (118 words)

  
 Definitions of the SI Units and other Units of Measurement
The SI derived unit for the mass of a mole of substance and is measured in kilogram per mole.
The SI unit of radiation dose is the gray (Gy); one rad equals 0.01 gray or 10 milligrays.
The SI definition of the second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium-133 atom.
www.gordonengland.co.uk /conversion/sidef.htm   (7411 words)

  
 SI supplementary unit: Facts and details from Encyclopedia Topic   (Site not responding. Last check: 2007-10-24)
The steradian (ste from greek stereos, solid) is the si derived unit of solid angle, and the 3-dimensional equivalent of the radian....
The hertz (symbol hz) is the si unit of frequency....
The pascal (symbol pa) is the si unit of pressure....
www.absoluteastronomy.com /encyclopedia/s/si/si_supplementary_unit1.htm   (571 words)

  
 SI derived unit Information
Formally, their SI unit is simply the number 1, but they are given these special names, for use whenever the lack of a unit might be confusing.
The unit of angle is the angle subtended at the centre of a circle by an arc of the circumference equal in length to the radius of the circle.
The unit of solid angle is the solid angle subtended at the centre of a sphere of radius r by a portion of the surface of the sphere having an area r
www.bookrags.com /SI_derived_unit   (291 words)

  
 Diagram of relationships among the SI units
In the first column the symbols of the SI base units are shown in rectangles, with the name of the unit shown toward the upper left of the rectangle and the name of the associated base quantity shown in italic type below the rectangle.
In the diagram the derivation of each derived unit is indicated by arrows that bring in units in the numerator (solid lines) and units in the denominator (broken lines), as appropriate.
Two SI derived units with special names and symbols, the radian, symbol rad, and the steradian, symbol sr (bottom of the third column of the diagram), are shown without any connections to SI base units -- either direct or through other SI derived units.
physics.nist.gov /cuu/Units/SIdiagram.html   (493 words)

  
 IEC - IEC in action | SI zone > The SI system   (Site not responding. Last check: 2007-10-24)
Derived units are obtained in terms of the base units according to a system of equations relating the corresponding quantities.
The SI derived units are obtained from the SI base units according to the International System of Quantities, or ISQ.
For example, the SI derived unit of speed is metre per second (m/s), because the derived quantity speed in the ISQ is defined as length divided by time.
www.iec.ch /zone/si/si_system.htm   (324 words)

  
 YourArt.com >> Encyclopedia >> watt   (Site not responding. Last check: 2007-10-24)
The watt (symbol: W) is the SI derived unit of power.
The watt is named after James Watt for his contributions to the development of the steam engine, and was adopted by the Second Congress of the British Association for the Advancement of Science in 1889 and by the 11th Conférence Générale des Poids et Mesures in 1960.
SI prefixes can be used, for example megawatt electrical (MWe) and gigawatt electrical (GWe).
www.yourart.com /research/encyclopedia.cgi?subject=/watt   (344 words)

  
 Becquerel -   (Site not responding. Last check: 2007-10-24)
The becquerel (symbol Bq) is the SI derived unit of radioactivity, defined as the activity of a quantity of radioactive material in which one nucleus decays per second.
As for all SI units whose names are derived from the proper name of a person, the first letter of its symbol is uppercase (Bq).
But when an SI unit is spelled out, it should always be written in lowercase (becquerel), unless it begins a sentence or is the name "degree Celsius".
psychcentral.com /psypsych/Becquerel   (355 words)

  
 SI base unit -   (Site not responding. Last check: 2007-10-24)
The unit of mass is equal to the mass of the international prototype kilogram (a platinum-iridium cylinder) kept at the Bureau International des Poids et Mesures (BIPM), Sèvres, Paris (1st CGPM (1889), CR 34-38).
The unit of time is the duration of exactly 9 192 631 770 periods of the radiation corresponding to the transition between two hyperfine levels of the ground state of the caesium-133 atom at a temperature of 0 K (13th CGPM (1967-1968) Resolution 1, CR 103).
The unit of length is equal to the length of the path travelled by light in a vacuum during the time interval of 1/299 792 458 of a second (17th CGPM (1983) Resolution 1, CR 97).
psychcentral.com /psypsych/SI_base_unit   (553 words)

  
 SI - Wikipedia Light!   (Site not responding. Last check: 2007-10-24)
The SI is not static; it is a living set of standards where units are created and definitions are modified with international agreement as measurement technology progresses.
Since most non-SI units, such as the U.S. customary units, are nowadays defined in terms of SI units, any change in the definition of the SI units results in a change of the definition of the older units as well.
ISO 1000:1992 SI units and recommendations for the use of their multiples and of certain other units, with its price tag of 99 Swiss francs for a 22 page, coverless pamphlet showing why the public is sometimes a little slow to pick up on their recommendations.
www.bostoncoop.net /~tpryor/wiki/index.php?title=International_System_of_Units   (1685 words)

  
 What is International System of Units? - a definition from Whatis.com - see also: SI
The meter (abbreviation, m) is the SI unit of displacement or length.
The kilogram (abbreviation, kg) is the SI unit of mass.
SI derived units include the hertz, the newton, the pascal (unit of pressure or stress), the ohm, the farad, the joule, the coulomb, the tesla, the lumen, the becquerel, the
whatis.techtarget.com /definition/0,,sid9_gci523539,00.html   (579 words)

  
 Articles - Ohm   (Site not responding. Last check: 2007-10-24)
The ohm (symbol: Ω) is the SI unit of electrical impedance or, in the direct current case, electrical resistance.
As for all SI units whose names are derived from the proper name of a person, the first letter of its symbol is uppercase (Ω).
But when an SI unit is spelled out, it should always be written in lowercase (ohm), unless it begins a sentence or is the name "degree Celsius".
www.worldhammock.com /articles/Ohm   (663 words)

  
 Int'l System of Units
Examples of such SI derived units are given in Table 3, where it should be noted that the symbol 1 for quantities of dimension 1 such as mass fraction is generally omitted.
The radian and steradian may be used advantageously in expressions for derived units to distinguish between quantities of a different nature but of the same dimension; some examples are given in Table 5.
For a graphical illustration of how the 22 derived units with special names and symbols given in Table 4 are related to the seven SI base units, see relationships among SI units.
www.sas.org /SIUnits.html   (425 words)

  
 SkyScopes SI Derived Science Formula Information Page
The radian and steradian may be used with advantage in expressions for derived units to distinguish between quantities of different nature but the same dimension.
In practice, the symbols rad and sr are used where appropriate, but the derived unit "1" is generally omitted.
This unit may be used in combination with SI prefixes, e.g.
www.skyscopes.com /scope/siderived.html   (85 words)

  
 ipedia.com: SI base unit Article   (Site not responding. Last check: 2007-10-24)
One second is defined as the time required for 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of caesium 133.
Unit: ampere (A) The ampere is that constant current which, if maintained in two straight parallel conductorss of infinite length, of negligible circular cross-section, and placed 1 metre apart in vacuum, would produce between these conductors a force equal to 2 × 10
The ampere is one of two base units (the other being the candela) that is not defined purely in terms of base units.
www.ipedia.com /si_base_unit.html   (474 words)

  
 Radiometry vs. photometry FAQ
The SI was adopted by the CGPM in 1960.
The lumen is an SI derived unit for luminous flux.
The lumen is derived from the candela and is the luminous flux emitted into unit solid angle (1 sr) by an isotropic point source having a luminous intensity of 1 candela.
www.optics.arizona.edu /Palmer/rpfaq/rpfaq.htm   (4296 words)

  
 FAQ: Frequently Asked Questions about the metric system
SI unit symbols are exactly that — symbols — and have fixed forms.
Unit symbols are not abbreviations, so they are not followed by a period (unless at the end of a sentence).
Using SI units — kilograms for m, meters per second squared for a, and newtons for F — that equation is literally true: just plug in the numbers.
lamar.colostate.edu /~hillger/faq.htm   (6684 words)

  
 Measurement   (Site not responding. Last check: 2007-10-24)
The unit of luminous intensity, the candela, is defined as 1/60 of the light radiated from a square centimetre of a flbody, a perfect radiator that absorbs no light, held at the temperature of freezing platinum.
The elementary unit must be specified and may be an atom, a molecule, an ion, an electron, a photon etc., or a given group of such entities.
Similarly, quantity of electricity (or electric charge) is equal to electric current multiplied by time so that the SI derived unit of quantity of electricity is the ampere second (A.s) which is given the special name of coulomb (C).
www.swin.edu.au /tafe/eis/indsci/wakeup/forensic/unit3/Measurmt.htm   (1145 words)

  
 Ohm - Wikipedia, the free encyclopedia
The ohm is the SI derived unit of electrical resistance (derived from the ampere and the watt).
This can also be represented in SI base units; a device that dissipates one watt of power with one ampere of current flowing through it has a resistance of one ohm (R = P/I
A measurement in ohms is the reciprocal of a measurement in siemens (also called mho, the anagram of ohm), the SI unit of electrical conductance.
www.encyclopedia-online.info /Ohm   (226 words)

  
 SI (en)
SI base unit Symbol Name Base quantity m metre; US: meter length kg kilogram mass s second time A ampere electrical current K kelvin thermodynamic temperature mol mole amount of substance cd candela luminous intensity The mass is commonly called the weight in people's daily life and trade.
The International System of Units (SI) is the modern metric system and adopted by the International Organization for Standardization (ISO) as International Standard ISO 1000.
The United States signed the Convention of the Metre (Meter Convention in American English) in 1875, but limited use of the SI and overuse of the inch-pound units cause obstacles.
www.geocities.com /jusjih/si-en.html   (792 words)

  
 BIPM - SI
The base units are a choice of seven well-defined units which by convention are regarded as dimensionally independent: the metre, the kilogram, the second, the ampere, the kelvin, the mole, and the candela.
Derived units are those formed by combining base units according to the algebraic relations linking the corresponding quantities.
The names and symbols of some of the units thus formed can be replaced by special names and symbols which can themselves be used to form expressions and symbols of other derived units.
www.bipm.fr /en/si   (187 words)

  
 methods
Other units of measure were derived from the SI base units and are called SI-derived units.
Since space is three-dimensional, a unit of volume is the cube of a unit of length, such as centimeters, feet, inches, or meters.
The SI base unit for mass is the kilogram, which is 1000 grams.
www.ruf.rice.edu /~bioslabs/methods/solutions/units.html   (498 words)

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