Unit Prefixes - Maple Help
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Unit Prefixes

 

Description

International System of Units (SI)

International Electrotechnical Commission (IEC)

Examples

References

Description

• 

To write multiples of units in an abbreviated form and avoid unnecessarily large or small powers, both the International System of Units (SI) and the International Electrotechnical Commission (IEC) have approved lists of prefixes that can be used in conjunction with certain units.

• 

For each multiple, the prefix can be attached to the unit name and the prefix symbol can be attached to the unit symbol.  For example, centimeter and cm.  The prefix cannot be attached to the symbol and the prefix symbol cannot be attached to the unit name.  For example, cmeter and centim are not accepted as units.

• 

A prefix must be used in conjunction with a unit. It cannot be used to represent numerical values.  For example, k does not represent 1000.

• 

Prefixes cannot be combined into compound prefixes. For example, use nanometer, not millimicrometer.

• 

The column titled Prefixes in the table describing the units of a given dimension, eg. length, shows whether a unit may be prefixed, and according to which of the conventions listed below. The ability to prefix a unit, and by which convention, can be determined programmatically using the GetUnit command.

International System of Units (SI)

Factor

Prefix

Symbol

Adopted

Etymology

 

 

 

 

 

quetta

Q

2022

decem [1], ten in Latin

ronna

R

2022

ennea / novem [1], nine in Greek and Latin, resp.

yotta

Y

1991

otto, eight in Italian

zetta

Z

1991

sette, seven in Italian

exa

E

1975

hex, six in Greek

peta

P

1975

pente, five in Greek

tera

T

1960

teras, monster in Greek

giga

G

1960

gigas, giant in Greek

mega

M

1960

megas, huge in Greek

1000

kilo

k

1795

khilioi, thousand in Greek

100

hecto

h

1795

hekaton, hundred in Greek

10

deka

da, dk

1795

deka, ten in Greek

 

 

 

 

 

1/10

deci

d

1795

decimus, tenth in Latin

1/100

centi

c

1795

centum, hundred in Latin

1/1000

milli

m

1795

mille, thousand in Latin

micro

, u, mc

1960

mikros, small in Greek

nano

n

1960

nanos, dwarf in Greek

pico

p

1960

piccolo, little bit in Spanish

femto

f

1964

femten, 15 in Norwegian/Danish

atto

a

1964

atten, 18 in Norwegian/Danish

zepto

z

1991

sept, seven in Greek

yocto

y

1991

okto, eight in Greek

ronto

r

2022

ennea / novem [1], nine in Greek and Latin, resp.

quecto

q

2022

decem [1], ten in Latin

 

 

 

 

 

• 

The correct symbol for the prefix deka is da, but dk is common in the United States.  The correct symbol for the prefix micro is the greek letter . Because the SI does not give an acceptable alternative in an ASCII environment, three prefix symbols have gained acceptance in various fields: u, mu, and mc. Any of these prefix symbols is valid in the Units package.

• 

In 1960, at the 10th CGPM, the prefix myria for 10000 was removed from the list of accepted prefixes.

International Electrotechnical Commission (IEC)

• 

The natural base for computers is . Since  is approximately equal to , the term kilobytes, referring to  bytes, was accepted.

• 

In 1998, to remove any possible confusion as to whether kilo refers to a multiplier of  or , the IEC approved a list of names and symbols for binary powers. This list was extended in 2005.

Factor

Prefix

Symbol

Example

 

 

 

 

kibi

Ki

1 kibibyte = KiB = 1024 bytes

mebi

Mi

1 mebibyte = MiB = 1048576 bytes

gibi

Gi

1 gibibyte = GiB = 1073741824 bytes

tebi

Ti

1 tebibyte = TiB = 1099511627776 bytes

pebi

Pi

1 pebibyte = PiB = 1125899906842624 bytes

exbi

Ei

1 exbibyte = EiB = 1152921504606846976 bytes

zebi

Zi

1 zebibyte = ZiB = 1180591620717411303424 bytes

yobi

Yi

1 yobibyte = YiB = 1208925819614629174706176 bytes

 

 

 

 

• 

The progression of Ki, Mi, Gi, Ti, Pi, Ei, Zi, Yi is similar to that of the SI prefixes, k, M, G, T, P, E, Z, Y, though for consistency, Ki is capitalized.

• 

Note that by default, the symbol B is reserved for unit bel. To change this, use the AddUnit routine.

Examples

(1)

(2)

(3)

(4)

(5)

(6)

(7)

References

  

[1] R. Brown, Discussion on the possible extension of the available range of SI prefixes. BIPM CCU/2019-10_04.

See Also

convert/units

Units

Units/AddUnit

Units/Index

 


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