---
title: "An ideal parallel-plate capacitor with plate separation distance \\(d\\) carries charge \\(+Q\\) on its top plate and charge \\(-Q\\) on its bottom plate. Three points, \\(P_1\\), \\(P_2\\), and \\(P_3\\), are located between the plates along a central vertical line at distances of \\(0.2d\\), \\(0.5d\\), and \\(0.8d\\) below the top plate, respectively. Neglecting fringe effects, which of the following correctly ranks the electric field energy density \\(u\\) at points \\(P_1\\), \\(P_2\\), and \\(P_3\\)?"
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url: "https://nerd-notes.com/ubq/118210/"
date_modified: "2026-08-04T08:08:11+00:00"
---

# An ideal parallel-plate capacitor with plate separation distance \(d\) carries charge \(+Q\) on its top plate and charge \(-Q\) on its bottom plate. Three points, \(P_1\), \(P_2\), and \(P_3\), are located between the plates along a central vertical line at distances of \(0.2d\), \(0.5d\), and \(0.8d\) below the top plate, respectively. Neglecting fringe effects, which of the following correctly ranks the electric field energy density \(u\) at points \(P_1\), \(P_2\), and \(P_3\)?

An ideal parallel-plate capacitor with plate separation distance \(d\) carries charge \(+Q\) on its top plate and charge \(-Q\) on its bottom plate. Three points, \(P_1\), \(P_2\), and \(P_3\), are located between the plates along a central vertical line at distances of \(0.2d\), \(0.5d\), and \(0.8d\) below the top plate, respectively. Neglecting fringe effects, which of the following correctly ranks the electric field energy density \(u\) at points \(P_1\), \(P_2\), and \(P_3\)?

![A schematic showing two horizontal parallel plates separated by distance d. The top plate is labeled +Q and the bottom plate is labeled -Q. A vertical dashed line passes through the central region between the plates. Three points are marked on this line: point P_1 at a distance 0.2d below the top plate, point P_2 at a distance 0.5d below the top plate, and point P_3 at a distance 0.8d below the top plate. No other labels, lines, text, or axes appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1785830890-F36jPv.jpg)

- **A.** \(u_1 > u_2 > u_3\)
- **B.** \(u_3 > u_2 > u_1\)
- **C.** \(u_1 = u_2 = u_3\)
- **D.** \(u_2 > u_1 = u_3\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/118210/*