knowledge/science/physics/SI Units.md

47 lines
No EOL
1.7 KiB
Markdown

---
obj: concept
wiki: https://en.wikipedia.org/wiki/International_System_of_Units
rev: 2024-02-08
---
# SI Units
The International System of Units (SI) is a modern metric system that is widely used in [science](../Science.md), technology, and engineering. It was developed to provide a consistent and coherent framework for measuring physical quantities, and it includes seven base units and several derived units.
## Base Units:
The seven base units of the SI system are:
- [Meter](units/Meter.md) (m) - length
- [Kilogram](units/Kilogram.md) (kg) - mass
- [Second](units/Second.md) (s) - time
- [Ampere](units/Ampere.md) (A) - electric current
- [Kelvin](units/Kelvin.md) (K) - thermodynamic temperature
- [Mole](units/Mole.md) (mol) - amount of substance
- [Candela](units/Candela.md) (cd) - luminous intensity
## Prefixes
The SI system uses prefixes to represent multiples and submultiples of the base units. Here are some common prefixes used in the SI system:
| Prefix | Symbol | Multiple |
| ------ | ------ | ---------- |
| atto | `a` | $10^{-18}$ |
| femto | `f` | $10^{-15}$ |
| pico | `p` | $10^{-12}$ |
| nano | `n` | $10^{-9}$ |
| micro | `μ` | $10^{-6}$ |
| milli | `m` | $10^{-3}$ |
| centi | `c` | $10^{-2}$ |
| deci | `d` | $10^{-1}$ |
| Base | - | $10^{0}$ |
| deca | `da` | $10^{1}$ |
| hecto | `h` | $10^{2}$ |
| kilo | `k` | $10^{3}$ |
| mega | `M` | $10^{6}$ |
| giga | `G` | $10^{9}$ |
| tera | `T` | $10^{12}$ |
| peta | `P` | $10^{15}$ |
| exa | `E` | $10^{18}$ |
| zetta | `Z` | $10^{21}$ |
## Derived Units
#refactor #notnow -> add more units
### Electricity
- [Volt](units/Volt.md)