On Fri, 2025-10-31 at 21:02 +0000, [email protected] wrote: > On Fri, 31 Oct 2025, [email protected] wrote: > > > On Fri, Oct 31, 2025 at 04:23:46PM +0000, > > [email protected] wrote: > > > On Fri, 31 Oct 2025, Nicolas George wrote: > > > > > > > [email protected] (HE12025-10-31): > > > > > i run a command preceded by time and pipe it to mail > > > > > the results of time is not included in the mail > > > > > > > > > > time sleep 2 2>&1 | mail -s foo bar@localhost > > > > > > > > Try this: > > > > > > > > time sleep 3 | sleep 10 > > > > > > > > … observe carefully the output and deduce something important > > > > about > > > > time. > > > > > > > > > > that's easy > > > the electrons are moving near the speed of light > > > so time slows down :) > > > > The electrons move actually pretty slowly. It's the electrical > > field > > what moves quickly. > > > > Let's assume copper, at a density of 8.9 g/cm^3, and an atomic > > weight > > of 63.5: 1mm^3 of copper has 6.02*10^23 * 8.9 * 10^-3 * (1/63.5) > > atoms, > > i.e. 8.44 * 10^19 atoms, each contributing one electron to the > > conduction > > band (the last lone S1). At 1.6 * 10^-19 C, that makes 13.5C of > > charge > > available for conduction in each mm^3, which is a friggin' lot. > > > > If you push 1A across a wire with a cross section of 1mm^2, your > > electrons would be moving at 1/13.5 mm/s, i.e. 0.074 mm/s: I can > > hear the snails in my garden yawning :) > > > > I might have lost an order of magnitude here or there, but the kind > > of result is somewhat consistent with the dim memories I have from > > a > > former life... > > i worked maintenance in a factory so i can't argue with any of that > but please clarify > is this 0.074 mm/s along the length of the conductor > what about moving in other directions > how far does an electron actually travel in one second
An ampere is defined as one Coulomb of charge transfer per second. The Coulomb is related to Avogadro's number by the Faraday constant. One Coulomb is roiughly 6.242e18 elementary charges.
