SI Units
| Quantity | Unit | Symbol |
|---|---|---|
| electric current | ampere | A |
| thermodynamic temperature | kelvin | K |
| time | second | s |
| length | metre | m |
| mass | kilogramme | kg |
| luminous intensity | candela | cd |
| amount of substance | mole | mol |
Just recently the SI units have been redefined. See Redefinition of SI Units.
SI derived units
- joule (J)
- volt (V)
- watt (W)
- newton (N)
- momentum p = mv (
$ \frac{\text{kg m}}{\text{s}}$or$\text{kg m s}^{-1}$)
standard form
see standard notation maths page
unit prefixes
| Multiplication factor | Prefix | Symbol | Example | |
|---|---|---|---|---|
| – | $10^{30}$ |
quetta | Q | |
| – | $10^{27}$ |
ronna | R | |
| – | $10^{24}$ |
yotta | Y | |
| – | $10^{21}$ |
zetta | Z | |
| – | $10^{18}$ |
exa | E | |
| 1 000 000 000 000 000 | $10^{15}$ |
peta | P | |
| 1 000 000 000 000 | $10^{12}$ |
tera | T | |
| 1 000 000 000 | $10^{9}$ |
giga | G | |
| 1 000 000 | $10^{6}$ |
mega | M | |
| 1 000 | $10^{3}$ |
kilo | k | |
| 100 | $10^{2}$ |
hecta | h | |
| 10 | $10^{1}$ |
deca | da | |
| 1 | $10^{0}$ |
|||
| 0.1 | $10^{-1}$ |
deci | d | |
| 0.01 | $10^{-2}$ |
centi | c | |
| 0.001 | $10^{-3}$ |
milli | m | |
| 0.000 001 | $10^{-6}$ |
micro | $\mathbb{\mu}$ |
|
| 0.000 000 001 | $10^{-9}$ |
nano | n | |
| 0.000 000 000 001 | $10^{-12}$ |
pico | p | |
| 0.000 000 000 000 001 | $10^{-15}$ |
femto | f | |
| – | $10^{-18}$ |
atto | a | |
| – | $10^{-21}$ |
zepto | z | |
| – | $10^{-24}$ |
yocto | y | |
| – | $10^{-27}$ |
ronto | r | |
| – | $10^{-30}$ |
quecto | q |