SAT Subject Physics Practice Question 213: Answer and Explanation
59. The square shown is the same size in each of the following diagrams. In which diagram is the electrical potential energy of the pair of charges the greatest?
Correct Answer: E
The electrical potential energy of a pair of charges is given by kq1q2/r, where r is the distance between the charges. Therefore, the electrical potential energy of the pair of charges +Q and +Q will be greatest when the distance between them is the smallest. Of the five diagrams given, the charges are closest together in diagram E.