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Seven bases units (Table 1), growing number of Derived SI Units with Special Names and Symbols (Table 2), and Examples of Units including SI Units (Table 3).

Table 1: Base Units (Seven)

Physical quantity Name Symbol
Length, distance meter m
Mass, weight kilogram kg
Time second s
Electric current ampere A
Thermodynamic temperature kelvin K
Amount of substance mole mol
Luminous intensity candela cd

 

Table 2: Derived SI Units with Special Names and Symbols

Physical quantity Name Symbol Dimensions of unit
derived base
Plane angle radian rad   m · m–1 = 1
Solid angle steradian sr   m2 · m–2 = 1
Celsius temperature degree Celsius °C   K
Electric capacitance farad F C/V m–2 · kg–1 · s4 · A2
Electric charge coulomb C   s · A
Electric conductance siemens S A/V m–2 · kg–1 · s3 · A2
Electric potential difference volt V W/A m2 · kg · s–3 · A–1
Electric resistance ohm omega V/A m2 · kg · s–3 · A–2
Energy joule J N · m m2 · kg · s–2
Force newton N   m · kg · s–2
Frequency hertz Hz   s–1
Illuminance lux lx lm/m2 m2 · m–4 · cd = m–2 · cd
Inductance henry H Wb/A m2 · kg · s–2 · A–2
Luminous flux lumen lm cd · sr m2 · m–2 · cd = cd
Power watt W J/s m2 · kg · s–3
Pressure pascal Pa N/m2 m–1 · kg · s–2
Magnetic flux weber Wb V · s m2 · kg · s–2 · A–1
Magnetic flux density tesla T Wb/m2 kg · s–2 · A–1
Activity (referred
to a radionuclide)
becquerel Bq   s–1
Absorbed dose, specific
energy (imparted), kerma
gray Gy J/kg m2 · s–2
Dose equivalent,
ambient dose equivalent,
directional dose equivalent,
personal dose equivalent,
organ equivalent dose
sievert Sv J/kg m2 · s–2
Catalytic activity katal kat   s–1 · mol

 

Table 3: Examples of Units including SI Units

Physical quantity Name Symbol Dimensions of unit
base
dynamic viscosity pascal second Pa s m1 kg s1
moment of force newton metre N m m2 kg s2
surface tension newton per metre N/m kg s2
angular velocity radian per second rad/s m m1 s1 = s1
rad/s2 m m1 s2 = s2
W/m2 kg s3
m2 kg s2 K1
m2 s2 K1
joule per kilogram J/kg m2 s2
watt per metre kelvin W/(m K) m kg s3 K1
joule per cubic metre J/m3 m1 kg s2
volt per metre V/m m kg s3 A1
coulomb per cubic metre C/m3 m3 s A
coulomb per square metre C/m2 m2 s A
farad per metre F/m m3 kg1 s4 A2
henry per metre H/m m kg s2 A2
joule per mole J/mol m2 kg s2 mol1
joule per mole kelvin J/(mol K) m2 kg s2 K1 mol1
coulomb per kilogram C/kg kg1 s A
gray per second Gy/s m2 s3
watt per steradian W/sr m4 m2 kg s3 = m2 kg s3
watt per square metre steradian W/(m2 sr) m2 m2 kg s3 = kg s3
katal per cubic metre kat/m3 m3 s1 mol

 

Table 4: Units outside the SI that are accepted for use with the SI

Name Symbol Base SI unit Dimensions of unit
Value in SI units
minute (time) min s (second) 1 min = 60 s
hour (time) h s (second) 1 h = 60 min = 3600 s
day (time) d s (second) 1 d = 24 h = 86 400 s
° rad (radian) 1° = ( pi/180) rad
' rad (radian) 1' = (1/60)° = (pi/10 800) rad
'' rad (radian) 1'' = (1/60)' = (pi/648 000) rad
L m (meter) 1 L = 1 dm3 = 10-3 m3
t kg (kilogram) 1 t = 103 kg
Np - (a ratio) 1 Np = 1 (number one)
B - (a ratio) 1 B = (1/2) ln 10 Np
eV J (Joule) 1 eV = 1.602 18 x 10-19 J, approximately
u kg (kilogram) 1 u = 1.660 54 x 10-27 kg, approximately
ua m (meter) 1 ua = 1.495 98 x 1011 m, approximately

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