Fundamental Units

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Fundamental Units

There are four fundamental units used to measure mass, length, time, and current. The table below shows these four units as defined in the System International (SI) units.

To learn more about the Fundamental Units, their historical context and definitions go to :   http://physics.nist.gov/cuu/Units/current.html

 

Quantity

Unit

Abbreviation

mass

kilogram

kg

length

meter

m

time

second

s

current

ampere

A

Derived Units

 

Quantity

Unit

Abbreviation

Base Units

force

newton

N

kgm/s2

energy & work

joule

J

kgm2/s2

power

watt

W

kgm2/s3

pressure

pascal

Pa

kg/(ms2)

frequency

hertz

Hz

1/s

electric charge

coulomb

C

As

electric potential

volt

V

kgm2/(As3)

electric resistance

ohm

W

kgm2/(A2s3)

capacitance

farad

F

A2s4/(kgm2)

magnetic field

tesla

T

kg/(As2)

magnetic flux

weber

Wb

kgm2/(As2)

inductance

henry

H

kgm2/(s2A2)

 

SI Prefixes

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

 

 

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