AAMC FL Practice Exam

In terms of electric fields, where do the lines exit from?

1. Positive to negative

2. Negative to positive

3. Neutral to charged areas

4. Dissimilar charges only

The correct answer is: Positive to negative

Electric field lines are a visual representation of the direction and strength of an electric field. These lines originate from positive charges and terminate at negative charges, illustrating the direction of the electric force that a positive test charge would experience in the field. Therefore, saying that the lines exit from positive to negative accurately captures this fundamental principle of electrostatics. This convention arises from the definition of electric field direction: it is defined as the direction of the force that a positive charge would experience in that field. Thus, since positive charges exert repulsive forces on other positive charges and attract negative charges, the field lines extend outward from positive sources and converge toward negative sources. The other choices do not accurately reflect the behavior of electric field lines. Negative to positive would imply an unrealistic scenario where field lines are incorrectly visualized as emanating from a negative charge. Neutral to charged areas might imply interaction between neutral objects and charged fields, which is not how electric field lines are conventionally represented. Finally, while dissimilar charges create electric fields, the question specifically pertains to the originating point of the lines, which are exclusively from positive to negative charges.