## 1.2.3 Prefixes

Prefixes
Prefixes are the preceding factor used to represent very small and very large physical quantities in SI units.

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
Normal number to Prefixes
Example 3
0.255 s is equal to how many ms.
Answer
mili (m) = 0.001 or 10-3
To write a normal number with prefixes, we divide the number with the value of the prefixes
0.0255 s = 0.0255 ÷ 10-3 = 25.5 ms
Example 4
Convert 265,500,000 W into GW.
Answer
Gega (G) = 1,000,000,000 or 109
Therefore
265,500,000 W = 265,500,000 ÷ 109 = 0.2655GW

External Link
The NIST Reference on Prefixes

Interactive Animation

### 16 comments

1. latifah // April 27, 2010 at 6:48 AM
This comment has been removed by the author.
2. latifah // April 27, 2010 at 6:50 AM

mcm mana nak hafal dgn lebih mudah?tiada cara k..?

3. muchaChaz // September 30, 2010 at 6:11 PM

Tak Gemar Minum Kopi Di Suruh Minum Milo Nak Pepsi.

4. Zureen Rockstar // November 8, 2010 at 2:48 AM

awesome ! now i can read it on my laptop and have no worry about my bag being heavy :)

5. shobana // January 20, 2011 at 10:10 PM

macam mana nak tukar dari prefixes to prefixes? Contohnya 6.71 mg to pg.

6. park yanhae // January 26, 2011 at 10:50 PM

ubah ke asas dlu
from mg to g 1st then ubah balik ke pg

ex: 1st step
6.71 m g x ((1x 10^-3)/m) g
=6.71x10^-3g

2nd step
(6.71x10^-3g)x(1p/1x10^-12)g
=6.71x 10^9 pg

or trus buat

6.71mg x ((1x 10^-3)/m) g x
(1p/1x10^-12)g

potong2 n still get the same answer.. :)

7. tika // February 1, 2011 at 6:39 AM

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8. aisyah // May 23, 2011 at 3:17 AM
This comment has been removed by the author.
9. aisyah // May 23, 2011 at 3:17 AM

time kasih...
dah paham daH...

10. my2heart // October 24, 2011 at 5:19 PM

great !!! love diz note..<3

11. OmCry // November 8, 2011 at 3:13 AM

okay. knapa kat exmple 1 tbe2 ada 250? where it comes from?

12. NABILAH // January 10, 2012 at 4:48 AM

tak paham laa , camana nak dapat 250 dalam soalan first tuu ?

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15. Aishah Siti // November 23, 2015 at 4:17 AM
This comment has been removed by the author.
16. Sara who? // March 1, 2016 at 6:14 AM

you got the wrong prefix table, after kilo is kilo, hekto, deka, deci ....
kilo; 10^3
hekto; 10^2
deka; 10^-2
deci; 10^-3
centi; 10-6