Does the current SI system (or the old metric system) have a prefix for 1/100,000?
No, it does not because none is needed. Steps of 1000 between one unit and the next larger (or smaller) unit are sufficient.
It is true that steps of ten are used between 1 and 1000 and between 0.001 and 1 (namely; centi, deci, deka and hecto). These are vestiges of the early metric system and have not been entirely eradicated from the current SI. They are still officially acceptable and many people feel they should be kept. (Others, like I, don't.)
After the beginning, when a new unit was created for every multiple of ten, it was quickly realized that such a scheme would lead to too many units (ie, too many prefixes) and would therefore be difficult and clumsy. In all newer parts of SI, there are only steps are 1000. As it is there are 16 SI pefixes (including centi, deci, deka and hecto). Do you know all 16? (I do!*) But I'm not sure I could (or would want to) learn 48 prefixes that would be necessary if we wanted one for every step of 10 up and down the scale.
Regards, Bill Hooper Fernandina Beach, Florida, USA
deka 10 hecto 100 kilo 1000 (or 10^3) mega 10^6 giga 10^9 terra 10^12 peta 10^15 exa 10^18 zeta 10^21 yotta 10^24
and
deci 1/10 centi 1/100 milli 1/1000 (or 10^-3) micro 10^-6 nano 10^-9 pico 10^-12 femto 10^-15 atto 10^-18 zepto 10^-21 yocto 10^-24
OK, so I'm showing off. I did these from memory, then checked. I found only one error which I corrected above. I had omitted exa.
Do you need the symbols? Most of them are just the first one letter of each prefix, capitals for all those from mega on up, lower case for the rest. The only exception is the two letter prefix "da" for deka.
