Electric potential

Intermediate

Potential energy per unit charge.

Key relationV = kq/r

The potential V = U/q is the work per unit charge to bring a test charge from infinity. For a point charge V = kq/r. It's a scalar and easy to add.

Worked example

1 μC at 0.3 m: 30 kV.

Common mistake

Zero reference can be chosen, usually at infinity.

In more detail

Electric potential is the potential energy per unit charge, V = U/q. For a point charge, V = kq/r, with zero at infinity.

Batteries provide a potential difference that drives current.
Electron guns accelerate electrons through potential differences.
Engineers quote the electric potential of a high-voltage terminal to know how much energy a charge will gain moving to it.

Is potential the same as energy?

No. Potential is energy per unit charge, and it is a scalar.

Why choose zero at infinity?

It is a convenient reference, since fields become negligible far away.

Is potential the same as voltage?

Yes, voltage is the everyday name for a potential difference.