The potentials that have to be dealt with are often hundreds and sometimes thousands of volts, and insulation troubles are more serious than is generally appreciated.
Observations on mountain tops generally show high potentials near the ground.
It was early recognized that a complete metallic circuit would obviate troubles from varying earth potentials, and that if the outgoing and incoming branches of the circuit were parallel and kept, by transposition spiralling, or otherwise, at equal average distances from the disturbing wire, induction effects would likewise be removed.
For since electricity tends to move between points or conductors at different potentials, if the electricity is at rest on them the potential must be everywhere the same.
Let V 1 and V2 be the potentials of the plates, and let a charge Q be given to one of them.
How would you define potentials? Add your definition here.