Question

For a two-charge system in an external field, if the external potential is positive and uniform, how do the energy contributions of a positive and negative charge differ?

Options

• Neither charge's external field interaction matters

• The positive charge contributes positively while the negative charge contributes negatively

• Both contribute negative energy

• Both contribute equally to the total energy

Answer 1

If V(r) is positive and uniform, then for a positive charge q1 > 0, the term q1V(r1) is positive, while for a negative charge q2 < 0, the term q2V(r2) is negative. This reflects that positive charges are driven to lower potential regions (higher energy) while negative charges are driven to higher potential regions (lower energy) to minimize total energy.