Basic Engineering Mathematics, Fifth Edition

Units, prefixes and engineering notation 55

Table 8.3Common SI multiples

Prefix Name Meaning

G giga multiply by 10^9 i.e.× 1000000000

M mega multiply by 10^6 i.e.× 1000000

k kilo multiply by 10^3 i.e.× 1000

m milli multiply by 10−^3 i.e.×

1

103

=

1

1000

= 0. 001

μ micro multiply by 10−^6 i.e.×

1

106

=

1

1000000

= 0. 000001

n nano multiply by 10−^9 i.e.×

1

109

=

1

1000000000

= 0. 000000001

p pico multiply by 10−^12 i.e.×

1

1012

=

1

1000000000000

=

0.000000000001

Atime of 150nsmeans 150× 10 −^9 sor

150

109

s, which

is 0.000000150s,
i.e. 150 nanoseconds is written as 150ns and is equal to
150 thousand millionths of a second.
Aforce of 20 kNmeans 20× 103 N, which is 20000
newtons,
i.e. 20 kilonewtons is written as 20kN and is equal to
20 thousand newtons.

Acharge of 30μCmeans 30× 10 −^6 Cor

30

106

C, which

is 0.000030C,
i.e. 30 microcoulombs is written as 30μC and is equal
to 30 millionths of a coulomb.

Acapacitance of 45pFmeans 45× 10 −^12 For

45

1012

F,

which is 0.000000000045F,
i.e. 45 picofarads is written as 45pF and is equal to 45
million millionths of a farad.
In engineering it is important to understand what such
quantities as 15GHz, 40MV, 12mH, 150ns, 20kN,
30 μC and 45pF mean.

Now try the following Practice Exercise

PracticeExercise 32 SI units and common

prefixes (answers on page 343)

1. State the SI unit of volume.


2. State the SI unit of capacitance.
   3. State the SI unit of area.
   4. State the SI unit of velocity.
   5. State the SI unit of density.
   6. State the SI unit of energy.
   7. State the SI unit of charge.
   8. State the SI unit of power.
   9. State the SI unit of angle.


3. State the SI unit of electric potential.


4. State which quantity has the unit kg.


5. State which quantity has the unit symbol.


6. State which quantity has the unit Hz.


7. State which quantity has the unit m/s^2.


8. State which quantity has the unit symbol A.


9. State which quantity has the unit symbol H.


10. State which quantity has the unit symbol m.


11. State which quantity has the unit symbol K.


12. State which quantity has the unit Pa.


13. State which quantity has the unit rad/s.


14. What does the prefix G mean?


15. What isthe symbol and meaning of the prefix
    milli?