- The largest increase in potential energy occurs when the charge is moving north. This is because the charge is negative, so it acquires potential energy when moving
in the same direction of the field (viceversa, a positive charge when moving in the direction of the field it loses potential energy converting it into kinetic energy). The amount of potential energy gained is equal to the product of the charge and the distance covered:
- The second largest increase is when the charge is moving east. In this case, actually, the variation of potential energy is zero. This is because the charge is moving perpendicular to the field, and so it is moving along points with same potential. Therefore, in this case the variation of potential energy is zero:
- Finally, when the charge is moving south, it loses potential energy. This is because it is moving
against the electric field, and since it is a negative charge, in this direction it loses potential energy converting it into kinetic energy. Therefore, in this case: