How can the speed of electricity be calculated?
The speed of electricity is a tricky concept. There are two speeds, not just one. The first speed is the electron drift. The second is the wavefront speed. Electron drift is where the free electrons, not attached to the atoms of the material in which the electrons are found (e.g., a copper wire), actually move as a group in the direction from the negative end, where there is an excess of free electrons, to the positive end, where there is a dearth of free electrons. [See source.] The drift velocity v = mu E; where mu is the so-called electron mobility and E is the electrical field in volts/m or volts/cm. A typical drift velocity is v = 1,000 (120/100) = 1,200 cm/sec.for silicon (Si) at 300 deg K and a field E = 120 V/m. Si has an electron mobility of mu = 1,000 cm^2/volt-sec In mph, Si v ~ 30 mph…way slower than light speed. Amps, the current unit, is directly related to electron drift velocity. In fact amps are just so-many electrons (and their charges) traveling through a conductor
