---
title: "A parallel-plate capacitor with plate area \\(A\\) and plate separation \\(d\\) is charged to a potential difference \\(V_0\\) and then disconnected from the battery, isolating charges \\(+Q_0\\) and \\(-Q_0\\) on its plates. A solid dielectric slab of dielectric constant \\(\\kappa > 1\\) initially fills the entire volume between the plates. An external agent slowly withdraws the slab horizontally until it is completely removed from the region between the plates. Which of the following correctly identifies the direction of the net electrostatic force exerted by the capacitor on the slab while it is being withdrawn, and the sign of the work done by the electric field on the slab during the complete removal?"
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url: "https://nerd-notes.com/ubq/124836/"
date_modified: "2026-09-28T14:11:37+00:00"
---

# A parallel-plate capacitor with plate area \(A\) and plate separation \(d\) is charged to a potential difference \(V_0\) and then disconnected from the battery, isolating charges \(+Q_0\) and \(-Q_0\) on its plates. A solid dielectric slab of dielectric constant \(\kappa > 1\) initially fills the entire volume between the plates. An external agent slowly withdraws the slab horizontally until it is completely removed from the region between the plates. Which of the following correctly identifies the direction of the net electrostatic force exerted by the capacitor on the slab while it is being withdrawn, and the sign of the work done by the electric field on the slab during the complete removal?

A parallel-plate capacitor with plate area \(A\) and plate separation \(d\) is charged to a potential difference \(V_0\) and then disconnected from the battery, isolating charges \(+Q_0\) and \(-Q_0\) on its plates. A solid dielectric slab of dielectric constant \(\kappa > 1\) initially fills the entire volume between the plates. An external agent slowly withdraws the slab horizontally until it is completely removed from the region between the plates. Which of the following correctly identifies the direction of the net electrostatic force exerted by the capacitor on the slab while it is being withdrawn, and the sign of the work done by the electric field on the slab during the complete removal?

![Two horizontal parallel conducting plates of equal length are separated by a small vertical gap. The top plate is labeled \(+Q_0\) and the bottom plate is labeled \(-Q_0\). A rectangular dielectric slab of dielectric constant \(\kappa\) lies between the plates and extends partially out of the right side of the gap into the surrounding space. A single horizontal arrow points to the right from the right edge of the dielectric slab, indicating the direction of withdrawal. No other labels, lines, text, or axes appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1790604697-OVLGEl.jpg)

- **A.** Direction of force: Toward the interior of the capacitor; Sign of work: Negative
- **B.** Direction of force: Toward the interior of the capacitor; Sign of work: Positive
- **C.** Direction of force: Away from the interior of the capacitor; Sign of work: Negative
- **D.** Direction of force: Away from the interior of the capacitor; Sign of work: Positive

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/124836/*