To use the prefixes listed in Table A4, divide the value
of the unit by the value of the prefix, and then add the prefix to the unit.
TABLE A4 METRIC PREFIXES USED in ELECTRICITY
Prefix
(letter symbol)

Value


mega (M)

Million

1,000,000

kilo (k)

thousand

1,000

milli (m)

thousandth

0.001

micro ()

millionth

0.000,001

nano (n)

thousandmillionth

0.000,000,001

Pico (p)

millionmillionth

0.000,000,000,001

Powers of Ten
Another way to express large and small values is to
convert the value to powers of 10. This is a convenient way to express values
and keep the units in the basic unit notation, rather than converting from one
unit of measure to another unit that may be larger or smaller, as we did in
metric prefixes above.
Examples
of expressing numbers as power of 10 are shown in Table A5.
Rules
associated with powers of ten are as follows:
Rule
1: To express numbers larger than 1 as a
small number times a power of 10, move the decimal point to the left as many
places as desired. Then multiply the number obtained by 10 to a power that is
equal to the number of places moved.
Example: To convert 6,000,000, move the decimal
point 6 places to the left (6.000,000), then multiply 6 times 10 raised to a
power equal to the number of decimal places moved, obtaining 6 x 10^{6}.
6,000,000
= 6 x 10^{6}
Rule
2: To express numbers less than 1 as a whole
number times a power of 10, move the decimal point to the right as many places
as desired. Then multiply the number obtained by 10 to a negative power that is
equal to the number of places moved.
Example: To convert 0.004A, move the decimal
point 3 places to the right (004.), then multiply 4 by 10 raised to a negative
power equal to the number of decimal places moved, obtaining 4 x 10^{3}A.
0.004A
= 4 x 10^{3}A
Rule
3: To convert a number expressed as a
positive power of 10 to a decimal number, move the decimal point to the right
as many places as the value of the exponent.
Example: To convert 1 x 10^{3},
move the decimal point 3 places to the right (1000.0), then drop the multiple
of power of 10, obtaining 1,000.
1 x
10^{3} = 1,000
Rule
4: To convert a number expressed as a
negative power of 10 to a decimal number, move the decimal point to the left as
many places as the value of the exponent.
Example: To convert 5 x 10^{3}A, move
the decimal point 3 places to the left (0.005), then drop the multiple of the
power of 10, obtaining 0.005A.
5 x
10^{3}A = 0.005A
Rule
5: To multiply 2 or more numbers expressed as
powers of 10, multiply the coefficients to obtain the new coefficient, and add
the exponents to obtain the new exponent of 10.
Example: To multiply 2 x 10^{5} by 3 x
10^{3}, multiply 2 x 3 to get 6, then add the exponents of the powers
of 10, 5 + (3), to get an exponent of 2, obtaining a product of 6 x 10^{2}.
(2
x10^{5}) (3 x10^{3})=6x10^{2}
Rule
6: To divide powers of 10, use the formula:
Table
A6 shows the metric prefixes expressed as powers of 10.
Metric
Prefix Power of 10
mega
(M)

10^{6}

kilo
(k)

10^{3}

milli
(m)

10^{3}

micro
()

10^{6}

nano
(n)

10^{9}

pico
(p)

10^{12}

Electrical
units can be expressed in different, but equivalent, units by using prefixes
expressed in powers of 10.
Examples:
