Multiple choiceQuestion 1 · Recall
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By the end you can recall the five SI base quantities and their units, and write any derived unit in this syllabus as a product or quotient of base units.
The main symbols used in this lesson:
| Symbol | Meaning |
|---|---|
| charge |
The SI (Système International) system builds everything from a few base quantities. You need these five:
| Base quantity | Unit | Symbol |
|---|---|---|
| mass | kilogram | kg |
| length | metre | m |
| time | second | s |
| electric current | ampere | A |
| (thermodynamic) temperature | kelvin | K |
Two things to notice:
SI base units
The units of the base quantities: kilogram (kg), metre (m), second (s), ampere (A) and kelvin (K). Every other SI unit is defined as a product or quotient of these.