Item RG203001: Increasing the distance between two positively charges particles, decreases the amount of electrostatic potential energy in the system because potential energy decreases when the distance between like particles increases.
Two positively charged particles are positioned as pictured in Figure 1 below. A student moves the particles so that the distance between the two particles is increased as shown in Figure 2. He secures the particles in place so neither can move. The strength of the charges remains the same the whole time.
Which of the following statements correctly describes the change in electrostatic potential energy of the system of two particles from Figure 1 to Figure 2?
- The electrostatic potential energy decreased because as any two particles get further apart, they have less of an effect on each other.
- The electrostatic potential energy decreased because potential energy decreases when the distance between like particles increases.
- The electrostatic potential energy increased because potential energy increases when the distance between any two particles increases.
- The electrostatic potential energy did not changed because the only way to change the potential energy of a system of like particles is to change the strength of the charges.
- Distribution of Responses

- Scale Score for Item Difficulty
(200[Easy]-800[Difficult]) - 523
- Students Responding Correctly
Group | Correct | Total | Percent |
---|---|---|---|
Overall | 330 | 1134 | 29% |
Grades | |||
4–5 | N/A | N/A | N/A |
6–8 | 179 | 621 | 29% |
9–12 | 151 | 513 | 29% |
Gender | |||
Male | 154 | 563 | 27% |
Female | 170 | 542 | 31% |
Primary Language | |||
English | 273 | 949 | 29% |
Other | 47 | 149 | 32% |