Metric SI units

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The International System of Units is abbreviated “SI” from the French “le Système international d’unités”. SI is the modern form of the metric system and is a coherent and definable measurement system devised around multiples of ten. It is the planet’s most widely used system of measurement, both for everyday commerce and for engineering, science and technology.


Base SI units

Quantity
Unit
Symbol
Equivalent
Equivalent
Length
metre
m
 
 
Mass
kilogram
kg
 
 
Time
second
s
 
 
Electric current
ampere
A
C/s
 
Absolute temperature
kelvin
K
 
 
Amount of substance
mole
mol
 
 
Luminous intensity
candela
cd
 
 

Coherent derived SI units

Quantity
Unit
Symbol
Equivalent
Equivalent
Plane angle
radian
rad
 
 
Solid angle
steradian
sr
 
 
Frequency
hertz
Hz
1/s
 
Force
newton
N
kg m/s²
 
Energy
joule
J
Nm
 
Power
watt
W
J/s
VA
Electric Charge
coulomb
C
As
 
Voltage – potential difference
volt
V
W/A
 
Electrical capacitance
farad
F
C/V
 
Electrical resistance
ohm
W
V/A
 
Magnetic flux
weber
Wb
 
 
Magnetic flux density
tesla
T
 
 
Inductance
henry
H
 
 
Luminous Flux
lumen
lm
 
 
Illumination
lux
lx
lm/m²
 

Further reading


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