Final answer:
The net force on a third charge placed equidistant from an electric dipole will be away from the negative dipole charge and towards the positive dipole charge, due to the differences in the forces of attraction and repulsion.
Step-by-step explanation:
An electric dipole is a system of two equal but opposite charges separated by a fixed distance. A third charge, -q, placed equidistant from a dipole with charges +2q and -2q, will experience forces due to each of the dipole's charges. Because these forces have different directions, the net force will be determined by the vector sum of the individual forces acting on -q. The force due to the positive charge will attract the -q charge, while the force due to the negative charge will repel it.
Given that the third charge has the same magnitude as the positive charge but opposite in sign, and that the negative charge in the dipole has twice the magnitude of the -q charge, the repulsion between the -2q and -q charge is stronger than the attraction between the +2q and -q. Therefore, the net force on the third charge -q will be directed away from the -2q charge and towards the +2q charge.