SI system in FInland

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The International System of units SI consists of a set of base units, derived units and prefixes. This article series provides basic information about the SI units and how they are realised in Finland.

The seven base units of the seven base quantities in the SI are:

  SI base unit
Base quantity Name Symbol
length metre m
mass kilogram kg
time second s
electric current ampere A
temperature kelvin K
amount of substance mole mol
luminous intensity candela cd

The derived units can be formed by combining the base units according to the algebraic relations linking the corresponding quantities, for instance the SI coherent derived unit for density (mass density) is kg/m3. For some of the derived units a special name and special symbol is given, for instance, the derived unit for force is Newton, N (kg·m·s–2).

The SI prefixes are used to form decimal multiples and submultiples of SI units:

Factor Name Symbol Factor Name Symbol
101 deca da 10–1 deci d
102 hecto h 10–2 centi c
103 kilo k 10–3 milli m
106 mega M 10–6 micro µ
109 giga G 10–9 nano n
1012 tera T 10–12 pico p
1015 peta P 10–15 femto f
1018 exa E 10–18 atto a
1021 zetta Z 10–21 zepto z
1024 yotta Y 10–24 yokto y

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