At 3:20 PM 12/5/4, Robin van Spaandonk wrote: >In reply to Horace Heffner's message of Fri, 03 Dec 2004 10:57:47 -0900: >Hi, >[snip] >>BTW, I see the referenced medical web site uses "KeV". The prefix "k" >>(small k) is the standard prefix for kilo-, even though "M" is the standard >>prefix for mega-. > >Necessary, because lower case m is the prefix for milli.
Only absolutely necessary to get single character prefixes. They could have used M for kilo- and MM for mega- or some other multi-character arrangements like those used in the petrolium industry. It was the objective of the standardization to get rid of just those kinds of things, so yes, it was necessary. After M the abbreviations are all capitalized for the positive exponents, whether the negative exponent abbreviatons match on first letter or not. For example, 10^18 is "exa-" or prefix "E", yet 10^-18 is "atto" or prefix "a". Similarly true for peta- and femto-, tera- and pico-, and giga- and nano-. All the negative exponent prefixes have small letters. Regards, Horace Heffner
