In reply to Eric Walker's message of Mon, 29 Jun 2015 13:39:12 -0500: Hi, If electric fields in semiconductors propagated instantly, then they would be able to support infinite frequencies. In fact what we see is that the amplification of transistors deteriorates as the frequency goes up. This is also the reason that computers get faster as the transistors in them get smaller. They are closer together, so signals don't have to travel as far, so that it takes less time.
Electric fields in most conductors propagate at speeds lower than light speed. IIRC in copper the speed is about 2/3(?) light speed. >On Mon, Jun 29, 2015 at 10:09 AM, James Bowery <[email protected]> wrote: > >And from the abstract for "Measuring Propagation Speed of Coulomb Fields >> <http://arxiv.org/abs/1211.2913>": >> >> As a matter of fact the Liénard-Weichert retarded potential leads to a >> formula indistinguishable from the one obtained assuming that the electric >> field propagates with *infinite velocity*. >> >> >I think Bob had in mind the addition of an electron to a semiconductor >material. I was thinking about the addition of energy to the existing >electrons (e.g., by the absorption of a photon) and the propagation of the >new average energy, which might or might not be considered the propagation >of an electric field. Is this latter case covered by the empirical finding >above? Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
