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title: "Two identical point charges, each with charge \\(+Q\\), are fixed in place on the \\(y\\)-axis at \\(y = +a\\) and \\(y = -a\\). A particle of mass \\(m\\) and negative charge \\(-q\\) (where \\(q > 0\\)) is constrained to move along the \\(x\\)-axis and is released from rest at a small displacement, executing bounded oscillations about the origin. Assuming the electric potential energy is defined to be zero infinitely far from the fixed charges, which of the following graphs best represents the electric potential energy \\(U\\) of the system as a function of the particle’s position \\(x\\)?"
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url: "https://nerd-notes.com/ubq/124606/"
date_modified: "2026-09-28T14:08:48+00:00"
---

# Two identical point charges, each with charge \(+Q\), are fixed in place on the \(y\)-axis at \(y = +a\) and \(y = -a\). A particle of mass \(m\) and negative charge \(-q\) (where \(q > 0\)) is constrained to move along the \(x\)-axis and is released from rest at a small displacement, executing bounded oscillations about the origin. Assuming the electric potential energy is defined to be zero infinitely far from the fixed charges, which of the following graphs best represents the electric potential energy \(U\) of the system as a function of the particle’s position \(x\)?

Two identical point charges, each with charge \(+Q\), are fixed in place on the \(y\)-axis at \(y = +a\) and \(y = -a\). A particle of mass \(m\) and negative charge \(-q\) (where \(q > 0\)) is constrained to move along the \(x\)-axis and is released from rest at a small displacement, executing bounded oscillations about the origin. Assuming the electric potential energy is defined to be zero infinitely far from the fixed charges, which of the following graphs best represents the electric potential energy \(U\) of the system as a function of the particle's position \(x\)?

![A Cartesian coordinate system drawn in black with a horizontal axis labeled x and a vertical axis labeled y intersecting at an origin labeled O. On the vertical axis, exactly two identical open circular markers are located symmetrically at coordinates (0, a) and (0, -a), each labeled +Q to the right of the axis. On the horizontal axis, a single small filled circular marker is located at a positive coordinate x, labeled -q directly above the marker. A dashed horizontal line segment connects the origin to the position of -q. No other labels, lines, text, or axes appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1790604526-j5yKv3.jpg)

- **A.** Graph A
- **B.** Graph B
- **C.** Graph C
- **D.** Graph D

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/124606/*