47 lines
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1.7 KiB
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47 lines
No EOL
1.7 KiB
Markdown
---
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obj: concept
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wiki: https://en.wikipedia.org/wiki/International_System_of_Units
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rev: 2024-02-08
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---
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# SI Units
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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.
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## Base Units:
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The seven base units of the SI system are:
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- [Meter](units/Meter.md) (m) - length
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- [Kilogram](units/Kilogram.md) (kg) - mass
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- [Second](units/Second.md) (s) - time
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- [Ampere](units/Ampere.md) (A) - electric current
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- [Kelvin](units/Kelvin.md) (K) - thermodynamic temperature
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- [Mole](units/Mole.md) (mol) - amount of substance
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- [Candela](units/Candela.md) (cd) - luminous intensity
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## Prefixes
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The SI system uses prefixes to represent multiples and submultiples of the base units. Here are some common prefixes used in the SI system:
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| Prefix | Symbol | Multiple |
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| ------ | ------ | ---------- |
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| atto | `a` | $10^{-18}$ |
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| femto | `f` | $10^{-15}$ |
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| pico | `p` | $10^{-12}$ |
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| nano | `n` | $10^{-9}$ |
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| micro | `μ` | $10^{-6}$ |
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| milli | `m` | $10^{-3}$ |
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| centi | `c` | $10^{-2}$ |
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| deci | `d` | $10^{-1}$ |
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| Base | - | $10^{0}$ |
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| deca | `da` | $10^{1}$ |
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| hecto | `h` | $10^{2}$ |
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| kilo | `k` | $10^{3}$ |
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| mega | `M` | $10^{6}$ |
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| giga | `G` | $10^{9}$ |
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| tera | `T` | $10^{12}$ |
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| peta | `P` | $10^{15}$ |
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| exa | `E` | $10^{18}$ |
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| zetta | `Z` | $10^{21}$ |
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## Derived Units
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#refactor #notnow -> add more units
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### Electricity
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- [Volt](units/Volt.md) |