---
title: "A rigid, planar rectangular wire loop of resistance \\(R\\) is forced to rotate counterclockwise at a constant angular speed \\(\\omega\\) about a fixed vertical axis passing through its center. A uniform static magnetic field \\(\\vec{B}\\) is directed horizontally to the right across the region. At the instant shown in the top-down view, the plane of the loop is parallel to the magnetic field. Which of the following diagrams best represents the directions of the magnetic forces exerted by the external magnetic field on the left and right vertical segments of the loop at this instant?"
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url: "https://nerd-notes.com/ubq/123437/"
date_modified: "2026-09-28T11:58:36+00:00"
---

# A rigid, planar rectangular wire loop of resistance \(R\) is forced to rotate counterclockwise at a constant angular speed \(\omega\) about a fixed vertical axis passing through its center. A uniform static magnetic field \(\vec{B}\) is directed horizontally to the right across the region. At the instant shown in the top-down view, the plane of the loop is parallel to the magnetic field. Which of the following diagrams best represents the directions of the magnetic forces exerted by the external magnetic field on the left and right vertical segments of the loop at this instant?

A rigid, planar rectangular wire loop of resistance \(R\) is forced to rotate counterclockwise at a constant angular speed \(\omega\) about a fixed vertical axis passing through its center. A uniform static magnetic field \(\vec{B}\) is directed horizontally to the right across the region. At the instant shown in the top-down view, the plane of the loop is parallel to the magnetic field. Which of the following diagrams best represents the directions of the magnetic forces exerted by the external magnetic field on the left and right vertical segments of the loop at this instant?

![A top-down view schematic. A horizontal solid line segment represents the edge-on rectangular wire loop, centered on a central pivot point drawn as a circle with a central dot representing a vertical rotation axis. Three horizontal, parallel solid arrows labeled \vec{B} point to the right across the figure, spaced evenly. A curved counterclockwise arrow labeled \omega is drawn near the central pivot indicating counterclockwise rotation. The left end of the horizontal segment is labeled Left edge and the right end is labeled Right edge. No other labels, lines, text, or axes appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1790596715-JE04oS.jpg)

- **A.** Diagram A: \(\vec{F}_{\text{left}}\) directed downward and \(\vec{F}_{\text{right}}\) directed upward
- **B.** Diagram B: Both \(\vec{F}_{\text{left}}\) and \(\vec{F}_{\text{right}}\) directed to the right
- **C.** Diagram C: Both \(\vec{F}_{\text{left}}\) and \(\vec{F}_{\text{right}}\) directed inward toward the axis of rotation
- **D.** Diagram D: \(\vec{F}_{\text{left}}\) directed upward and \(\vec{F}_{\text{right}}\) directed downward

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/123437/*