SI (System of International) System of Units
SI (System of international) system of units
The SI system consists of seven basic units and two supplementary units. These are represented in table 1 . The unit for other quantities are derived from the basic units which are given in table 2.
It is convenient to use prefix to avoid the use of very large or very small numbers these prefix are given in table 3
BEST VIEW IN DESKTOP MODE
SI System : Basic Units
|
Quantity
|
Unit
|
Symbol
|
Fundamental units: Length (l) ( small L)
Mass (m)
Time (t)
Temperature (T)
Electric current (I) (Capital I)
Luminous intensity (Iv)
Amount of substance (n)
Supplementary units Plane angle
Solid angle
|
metre
kilogram
second
kelvin
ampere
candela
mole
radian steradian
|
m
kg
(s)
(K)
A
cd mol
(sr)
|
Table 1
SI System : Derived Units
|
Quantity
|
Unit
|
Symbol
|
|
Force
Energy
Power
Pressure
Density
Velocity
Acceleration
Angular velocity
Angular acceleration
Dynamic viscosity
Entropy
Specific heat
Thermal conductivity
|
newton
joule
watt
pascal
kilogram per cubic metre
metre per second
metre per second square
radian per second
radiation per second square
newton-second per square metre
joule per kelvin
joule per kilogram kelvin
watt per metre kelvin
|
N
J
W
Pa
kg/m³
m/s
m/s²
rad/s
rad/s²
N-s/m²
J/K
J/kgK
W/mK
|
Table 2
Preflxes used in Basic Units
|
Factor
|
prefix
|
Abbreviation
|
Factor
|
Prefix
|
Abbreviation
|
|
10¹²
10⁹
10⁶
10³
|
tera
giga
mega
kilo
|
T
G
M
k
|
10-3
10-6
10-9
10-12
|
mili
micro
nano
pico
|
m
μ
n
p
|
Table 3