# Use of SI Units & Their Prefixes

## Prefixes

A prefix can be placed at the beginning of a unit to signify a certain order of magnitude. You will have already come across some of them such as kilo ‘k’ which is a magnitude of 1000x.

The list that you are required to know is as follows:

The scaling factor is how to write the the value in standard form.

## SI Unit

An SI unit is a fundamental unit. This means that it cannot be broken down into other units.

There are seven fundamental or base units as shown below. Every other unit can be made up from these units.

## Derived Units

- What is the base unit charge?
- As
- What power of 10 does the symbol ‘n’ carry?
- 9
- List all of the SI units
- Your answer should include: Mass / Distance / Time / Current / Amount / Temperature / Light intensity