---
title: "A neutral solid conducting sphere is placed in the vicinity of a fixed positive point charge \\(+Q\\). A grounding wire connected to earth is attached to the sphere, allowed to reach electrostatic equilibrium, and then disconnected. The sphere is observed to retain a net negative charge rather than returning to a neutral state. Which of the following correctly explains why the grounded sphere acquires a net negative charge?"
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url: "https://nerd-notes.com/ubq/121150/"
date_modified: "2026-08-23T04:58:18+00:00"
---

# A neutral solid conducting sphere is placed in the vicinity of a fixed positive point charge \(+Q\). A grounding wire connected to earth is attached to the sphere, allowed to reach electrostatic equilibrium, and then disconnected. The sphere is observed to retain a net negative charge rather than returning to a neutral state. Which of the following correctly explains why the grounded sphere acquires a net negative charge?

A neutral solid conducting sphere is placed in the vicinity of a fixed positive point charge \(+Q\). A grounding wire connected to earth is attached to the sphere, allowed to reach electrostatic equilibrium, and then disconnected. The sphere is observed to retain a net negative charge rather than returning to a neutral state. Which of the following correctly explains why the grounded sphere acquires a net negative charge?

![A circular solid disc representing a conducting sphere is positioned to the right of a small filled circle labeled \(+Q\). A horizontal dashed line connects the center of \(+Q\) and the center of the sphere. Extending downward from the bottom of the sphere is a thin solid vertical line with an open switch symbol, leading to a standard ground symbol made of three horizontal parallel lines of decreasing width stacked vertically. No other labels, lines, text, or axes appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1787461098-p8FVhb.jpg)

- **A.** The ground connection provides a pathway for electrons to enter the sphere until the electric field in the interior reaches zero, which is only possible when the sphere acquires sufficient negative charge to terminate all field lines entering from the external charge.
- **B.** The external positive charge exerts a repulsive electrostatic force on mobile positive charge carriers in the sphere, driving them through the ground wire into the earth until only bound negative charges remain on the surface.
- **C.** The ground connection forces the total electric flux through any closed Gaussian surface enclosing both the point charge and the sphere to be zero, requiring the sphere to accumulate a negative charge of equal magnitude to the point charge.
- **D.** Grounding establishes an electrostatic potential of zero on the sphere relative to infinity, requiring negative charge to flow from ground onto the sphere until the potential produced by its net charge cancels the positive potential contributed by the external charge.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/121150/*