Electrical conductors

Metals are good conductors of electric current, silver being the best, with the lowest resistivity. In silver, copper etc. one electron per atom becomes a 'free' charge carrier, that moves slowly through the metal in response to a small electric field.

A current flows in a copper block (shown greatly enlarged and not to scale).

The volume of copper contains ten Coulombs of charge carriers (free electrons) and is 10 cm long. When a current of one Amp is flowing, the drift velocity of the electrons is one cm/s, a typical value for currents of ~one Amp in connecting wires.

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