Prefixes are the preceding factor used to represent very small and very large physical quantities in SI units.
Table below shows the prefixes that you need to know in SPM.
![](http://3.bp.blogspot.com/_PyvjcvYfRLk/SWF0_nbdOuI/AAAAAAAAAVI/hV9ebr5rDiM/s400/prefixes.png)
Conversion of prefixes
Prefixes to Normal Number
Example 1:
The frequency of the radio wave is 350M Hz. What is the frequency of the radio wave in Hz?
Answer:
Mega (M) = 1,000,000 or 106
Therefore,
350MHz = 350 x 106Hz
Example 2:
The thickness of a film is 25nm. What is the thickness in unit meter?
Answer:
nano (n) = 0.000000001 or 10-9
Therefore
25nm = 25 x 10-9m