En réponse à John Cowan <[log in to unmask]>: > > Wow, I always think of Ohm's law as R=I/V. To me "URI" suggests > Uniform Resource Identifier, one of those things beginning http:// > or ftp:// or urn:. (The ones that don't begin with urn: are > Uniform Resource Locators, or URLs.) > What's the use of urn:? I've never seen it in my life. > Why U for voltage/electromotive force? > In France, V is used for the potential itself. Potential differences are marked by U, so that we don't mistake potential (defined relative to an arbitrary constant) to electromotive force (defined absolutely). The difference is little, but believe me, it helps quite a lot to prevent simple mistakes. It's also quite useful when talking about motion driven by electric forces, since v is then taken for velocities :)) . He he, blame it on the French tendency to classify everything using labels that should be usable in any context :)) . Christophe. http://rainbow.conlang.free.fr Take your life as a movie: do not let anybody else play the leading role.