The potential energy of a charge, q, at a point in space where the voltage due to all charges except is V, is given by the formula

You can conceptually test for high and low potential energy by asking the question, ``Does the charge want to go there or not?'' If it is hard to get the test charge to go somewhere, then that is a place of high potential energy. If the test charge wants to go there, then it is a place of low potential energy. Notice that for a positive q, a place of high voltage is a place of high potential energy, but for a negative q, it is a place of low potential energy. To avoid confusion, when testing for high and low voltage, always use a positive test charge.

The total potential energy of a group of charges can be gotten by using the following formula for the potential energy of two point charges, and , separated by a distance :

The potential energy of the group is simply the sum of the potential energies for all the pairs of charges in the group. For instance, for a group of four charges the total potential energy would be

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