Appendix 7–2 SI Units (Système International d'Unités or International System of Units)
This system includes two types of units important in clinical medicine. The base units are shown in the first table, derived units in the second table, and derived units with special names in the third table.
SI BASE UNITS
| Quantity |
Name |
Symbol |
| Length |
meter |
m |
| Mass |
kilogram |
kg |
| Time |
second |
s |
| Electric current |
ampere |
A |
| Temperature |
kelvin |
K |
| Luminous intensity |
candela |
cd |
| Amount of a substance |
mole |
mol |
SOME SI DERIVED UNITS
| Quantity |
Name of Derived Unit |
Symbol |
| Area |
square meter |
m2
|
| Volume |
cubic meter |
m3
|
| Speed, velocity |
meter per second |
m/s |
| Acceleration |
meter per second squared |
m/s2
|
| Mass density |
kilogram per cubic meter |
kg/m3
|
| Concentration of a substance |
mole per cubic meter |
mol/m3
|
| Specific volume |
cubic meter per kilogram |
m3 /kg |
| Luminescence |
candela per square meter |
cd/m2
|
| Body mass index |
kilogram per meter squared |
kg/m2
|
SI DERIVED UNITS WITH SPECIAL NAMES
| Quantity |
Name |
Symbol |
Expressed in Terms of Other Units |
| Frequency |
hertz |
Hz |
s−1
|
| Force |
newton |
N |
kg·m·s−2 or kg·m/s2
|
| Pressure |
pascal |
Pa |
N·m−2 or N/m2
|
| Energy, work, amount of heat |
joule |
J |
kg·m2· s−2 or N·m |
| Power |
watt |
W |
J·s or J/s |
| Quantity of electricity |
coulomb |
C |
A·s |
| Electromotive force |
volt |
V |
W/A |
| Capacitance |
farad |
F |
C/V |
| Electrical resistance |
ohm |
Ω |
V/a |
| Conductance |
siemens |
S |
A/V |
| Inductance |
henry |
H |
Wφ/A |
| Illuminance |
lux |
lx |
ln/m2
|
| Absorbed (radiation) dose |
gray |
Gy |
J/kg |
| Dose equivalent (radiation) |
sievert |
Sv |
J/kg |
| Activity (radiation) |
becquerel |
Bq |
s−1
|
PREFIXES AND MULTIPLES USED IN SI
| Prefix |
Symbol |
Power |
Multiple or Portion of a Multiple |
| tera |
T |
1012
|
1,000,000,000,000. |
| giga |
G |
109
|
1,000,000,000. |
| mega |
M |
106
|
1,000,000. |
| kilo |
k |
103
|
1,000. |
| hecto |
h |
102
|
100. |
| deca |
da |
101
|
10. |
| unity |
|
|
1 |
| deci |
d |
10−1
|
0.1 |
| centi |
c |
10−2
|
0.01 |
| milli |
m |
10−3
|
0.001 |
| micro |
μ |
10−6
|
0.000001 |
| nano |
n |
10−9
|
0.000000001 |
| pico |
p |
10 −12
|
0.000000000001 |
| femto |
f |
10−15
|
0.000000000000001 |
| atto |
a |
10−18
|
0.000000000000000001 |
Appendix 7–2 SI Units (Système International d'Unités or International System of Units)
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