Units in physics
In physics there are lots of units. In physics a quantity is a property of an object. For example length and mass are quantities.
SI base units
SI base units are designed to standardise measurements across the world. It is used in not just physics but also medicine, engineering and many other fields. The SI base units are the fundamental units from which all other units are derived. Here are the seven SI base units:
| Quantity | Unit | Symbol |
|---|---|---|
| Length | metre | m |
| Mass | kilogram | kg |
| Time | second | s |
| Electric current | ampere | A |
| Thermodynamic temperature | kelvin | K |
| Amount of substance | mole | mol |
| Luminous intensity | candela | cd |
Prefixes
Prefixes are used to denote multiples or fractions of a unit. Here are some common prefixes:
| Prefix | Symbol | Factor |
|---|---|---|
| tera | T | 10^12 |
| giga | G | 10^9 |
| mega | M | 10^6 |
| kilo | k | 10^3 |
| hecto | h | 10^2 |
| deca | da | 10^1 |
| deca | da | 10^1 |
| deci | d | 10^-1 |
| centi | c | 10^-2 |
| milli | m | 10^-3 |
| micro | μ | 10^-6 |
| nano | n | 10^-9 |
| pico | p | 10^-12 |
| femto | f | 10^-15 |
See also
References
- A Level Physics OCR (Pages 8-9)
BOOK - Unit prefix - Wikipedia
WEB - SI base unit - Wikipedia
WEB - British Medical Journal - SI Units
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