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SI base unit

 

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SI base unit


 
 

The International System of UnitsInternational System of Units

The International System of Units is the modern form of the metric system....
 (SI) defines seven SI base units: physical units defined by an operational definitionOperational definition

An operational definition is a description of something—such as a variable, term, or object—in terms of the spe...
.

All other physical units can be derived from these base units: these are known as SI derived unitSI derived unit

SI derived units are part of the SI system of measurement units and are derived from the seven SI base units....
s. Derivation is by dimensional analysisDimensional analysis

Dimensional analysis is a conceptual tool often applied in physics, chemistry, and engineering to understand physical situat...
. SI prefixSI prefix

An SI prefix is a name or associated symbol that precedes a unit of measure to form a decimal multiple or submultiple....
es are used to abbreviate long numbers.

The following are the base units from which all others are derived; they are dimensionally independent.

See also

  • International System of Measurements
  • SI prefixSI prefix

    An SI prefix is a name or associated symbol that precedes a unit of measure to form a decimal multiple or submultiple....
  • meter
  • ampereAmpere

    The ampere is the SI base unit of electric current....
  • secondSecond

    The second is the name of a unit of time, and today refers to the International System of Units base unit of time....
  • speed of lightSpeed of light

    The speed of light in a vacuum is an important physical constant denoted by the letter c for constant or the Latin w...
  • electric constantElectric constant

    The electric constant is the permittivity of vacuum, a physical constant, defined by:...
  • magnetic constant
  • kelvinKelvin

    The Kelvin scale is a temperature scale where absolute zero—the coldest possible temperature where there is no heat en...
  • physical constantPhysical constant

    In physics, a physical constant is a physical quantity of a value that is generally believed to be both universal in nature ...


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