Question

In what scenario is the potential energy of a two-charge system given by the formula \[U = \frac{q_1q_2}{4\pi\varepsilon_0 r_{12}}\] with no additional terms?

Options

• When there is an external electric field present

• When the two charges are isolated from any external field

• When the charges are at equal distances from a field source

• When one charge is held fixed at infinity

Answer 1

The formula \[U = \frac{q_1q_2}{4\pi\varepsilon_0 r_{12}}\] represents the potential energy only for an isolated system of two charges with no external field. This is the simplest case, containing only the mutual Coulombic interaction term without any external field contributions.