---
title: "Two charged insulating spheres, Sphere X with net charge \\(+Q\\) and Sphere Y with net charge \\(+3Q\\), are fixed a distance \\(d\\) apart. Due to mutual electrostatic forces, bound surface charges on both spheres shift slightly within their molecular structures as the spheres polarize each other. Which of the following claims correctly compares the magnitude of the electrostatic force \\(F_{\\text{X on Y}}\\) exerted by Sphere X on Sphere Y to the magnitude of the electrostatic force \\(F_{\\text{Y on X}}\\) exerted by Sphere Y on Sphere X, and provides a correct physical justification?"
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url: "https://nerd-notes.com/ubq/117349/"
date_modified: "2026-08-04T06:51:54+00:00"
---

# Two charged insulating spheres, Sphere X with net charge \(+Q\) and Sphere Y with net charge \(+3Q\), are fixed a distance \(d\) apart. Due to mutual electrostatic forces, bound surface charges on both spheres shift slightly within their molecular structures as the spheres polarize each other. Which of the following claims correctly compares the magnitude of the electrostatic force \(F_{\text{X on Y}}\) exerted by Sphere X on Sphere Y to the magnitude of the electrostatic force \(F_{\text{Y on X}}\) exerted by Sphere Y on Sphere X, and provides a correct physical justification?

Two charged insulating spheres, Sphere X with net charge \(+Q\) and Sphere Y with net charge \(+3Q\), are fixed a distance \(d\) apart. Due to mutual electrostatic forces, bound surface charges on both spheres shift slightly within their molecular structures as the spheres polarize each other. Which of the following claims correctly compares the magnitude of the electrostatic force \(F_{\text{X on Y}}\) exerted by Sphere X on Sphere Y to the magnitude of the electrostatic force \(F_{\text{Y on X}}\) exerted by Sphere Y on Sphere X, and provides a correct physical justification?

![Two insulating spheres labeled X and Y are drawn along a horizontal axis separated by distance d. Sphere X on the left is smaller and labeled +Q at its center. Sphere Y on the right is larger and labeled +3Q at its center. A horizontal dashed line connects their centers, with a double-headed arrow below labeled d. Positive surface charges on both spheres are drawn slightly concentrated toward the outer edges away from each other to represent polarization. No other labels, lines, text, or axes appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1785826313-Vp4Ebe.jpg)

- **A.** \(F_{\text{X on Y}} < F_{\text{Y on X}}\) because Sphere Y carries a greater net charge, producing a stronger electric field at the location of Sphere X.
- **B.** \(F_{\text{X on Y}} > F_{\text{Y on X}}\) because the larger charge of Sphere Y causes greater polarization in Sphere X than Sphere X causes in Sphere Y.
- **C.** \(F_{\text{X on Y}} = F_{\text{Y on X}}\) because the electrostatic forces exerted by the spheres on each other form an action-reaction pair governed by Newton's third law.
- **D.** \(F_{\text{X on Y}} = F_{\text{Y on X}}\) because insulating materials cannot undergo electrostatic polarization, leaving both charge distributions perfectly uniform.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/117349/*