leichter@yale-com.UUCP (06/27/83)
"The speed of electricity" is not a particularly meaningful term. If you ask "how fast do electrons move through a wire", the answer is "very slowly" (a couple of feet per second, at most). However, this is not a figure of much interest. A meaningful question is "How fast can a message be propagated?" (where "message" is very general - it includes the the "message" that the wall switch has been closed "telling" the light bulb to light up), the answer to which is again complicated - because it depends on the exact circuitry - but is something on the order of half the speed of light in a vacuum. A good rule of thumb is that light travels about a foot per nanosecond, so electrical impulses in typical circuitry travel at about 6-8 inches or so per nanosecond. This works out to something like 1/100 of a second to cross the US. -- Jerry decvax!yale-comix!leichter leichter@yale
leichter@yale-com.UUCP (06/27/83)
More to go with my previous note: You ask how long it would take a "bolt" to travel some distance. The only meaningful interpretation I can make is that you mean a lightning bolt. I've never seen any figures on the speed of propagation for lightning flashes through the air, but it's a very complex process in which the air is heated & ionized; the propagation rate would be well below lightspeed. -- Jerry