Kilo-
Kilois adecimalunit prefixin themetric systemdenoting multiplication by onethousand(103). It is used in theInternational System of Units,where it has the symbolk,inlowercase.
The prefixkilois derived from theGreekwordχίλιοι(chilioi), meaning "thousand".
In 19th century English it was sometimes spelled chilio, in line with apuristicopinion byThomas Young.[1][2]As an opponent of suggestions to introduce the metric system in Britain, he qualified the nomenclature adopted in France as barbarous.
Examples
[edit]- onekilogram(kg) is 1000grams
- onekilometre(km) is 1000metres
- onekilojoule(kJ) is 1000joules
- one kilolitre (kL) is 1000litres
- one kilobaud (kBd) is 1000bauds
- one kilohertz (kHz) is 1000hertz
- one kilodalton (kDa) is 1000daltons
- onekilobit(kb) is 1000bits
- onekilobyte(kB) is 1000bytes
- one kiloohm is (kΩ) is 1000ohms
- onekilosecond(ks) is 1000seconds
- onekilotonne(kt) is 1000tonnes
By extension, currencies are also sometimes preceded by the prefix kilo-:
kilobyte
[edit]For the kilobyte, a second definition has been in common use in some fields ofcomputer scienceand information technology. It useskilobyteto mean 210bytes (= 1024 bytes), because of themathematical coincidencethat 210is approximately 103.The reason for this application is that digital hardware and architectures natively usebase 2exponentiation, and notdecimalsystems.JEDEC memory standardsstill permit this definition, but acknowledge the correct SI usage.
NIST comments on the confusion caused by these contrasting definitions: "Faced with this reality, theIEEE Standards Boarddecided that IEEE standards will use the conventional, internationally adopted, definitions of the SI prefixes ", instead of kilo for 1024.[3]To address this conflict, a new set ofbinary prefixeshas been introduced, which is based on powers of 2. Therefore, 1024 bytes are defined as onekibibyte(1 KiB).
Exponentiation
[edit]When units occur inexponentiation,such as in square and cubic forms, any multiplier prefix is considered part of the unit, and thus included in the exponentiation.
- 1 km2means one square kilometre or the area of asquarethat measures 1000 m on each side or 106m2(as opposed to 1000 square meters, which is the area of a square that measures 31.6 m on each side).
- 1 km3means one cubic kilometre or the volume of acubethat measures 1000 m on each side or 109m3(as opposed to 1000 cubic meters, which is the volume of a cube that measures 10 m on each side).
See also
[edit]- milli-(inverse of kilo- prefix, denoting a factor of 1/1000)
- kibi-(binary prefix, denoting a factor of 1024)
- RKM code
References
[edit]- ^Brewster, David (1832).The Edinburgh Encyclopaedia.Vol. 12 (1st American ed.). Joseph and Edward Parker.Retrieved2015-10-09.
- ^Dingler, Johann Gottfried (1823).Polytechnisches Journal(in German). Vol. 11. Stuttgart, Germany: J.W. Gotta'schen Buchhandlung.Retrieved2015-10-09.
- ^Definition of binary prefixes at NIST
Prefix | Base 10 | Decimal | Adoption [nb 1] | |
---|---|---|---|---|
Name | Symbol | |||
quetta | Q | 1030 | 1000000000000000000000000000000 | 2022[1] |
ronna | R | 1027 | 1000000000000000000000000000 | |
yotta | Y | 1024 | 1000000000000000000000000 | 1991 |
zetta | Z | 1021 | 1000000000000000000000 | |
exa | E | 1018 | 1000000000000000000 | 1975[2] |
peta | P | 1015 | 1000000000000000 | |
tera | T | 1012 | 1000000000000 | 1960 |
giga | G | 109 | 1000000000 | |
mega | M | 106 | 1000000 | 1873 |
kilo | k | 103 | 1000 | 1795 |
hecto | h | 102 | 100 | |
deca | da | 101 | 10 | |
— | — | 100 | 1 | — |
deci | d | 10−1 | 0.1 | 1795 |
centi | c | 10−2 | 0.01 | |
milli | m | 10−3 | 0.001 | |
micro | μ | 10−6 | 0.000001 | 1873 |
nano | n | 10−9 | 0.000000001 | 1960 |
pico | p | 10−12 | 0.000000000001 | |
femto | f | 10−15 | 0.000000000000001 | 1964 |
atto | a | 10−18 | 0.000000000000000001 | |
zepto | z | 10−21 | 0.000000000000000000001 | 1991 |
yocto | y | 10−24 | 0.000000000000000000000001 | |
ronto | r | 10−27 | 0.000000000000000000000000001 | 2022[1] |
quecto | q | 10−30 | 0.000000000000000000000000000001 | |
|
- ^ab"On the extension of the range of SI prefixes".18 November 2022.Retrieved5 February2023.
- ^"Metric (SI) Prefixes".NIST.