---
title: "An infinitely long, straight wire lies along the \\(y\\)-axis and carries a constant current \\(I_1\\) in the \\(+y\\)-direction. A separate, straight wire segment of length \\(L\\) lies in the \\(xy\\)-plane along the \\(x\\)-axis from \\(x = d\\) to \\(x = d + L\\), where \\(d > 0\\), and carries a constant current \\(I_2\\) in the \\(+x\\)-direction. Which of the following diagrams best represents the direction and relative magnitude of the magnetic force per unit length, \\(d\\vec{F}/dx\\), exerted on the horizontal wire segment by the magnetic field of the long wire?"
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url: "https://nerd-notes.com/ubq/124908/"
date_modified: "2026-09-28T14:11:54+00:00"
---

# An infinitely long, straight wire lies along the \(y\)-axis and carries a constant current \(I_1\) in the \(+y\)-direction. A separate, straight wire segment of length \(L\) lies in the \(xy\)-plane along the \(x\)-axis from \(x = d\) to \(x = d + L\), where \(d > 0\), and carries a constant current \(I_2\) in the \(+x\)-direction. Which of the following diagrams best represents the direction and relative magnitude of the magnetic force per unit length, \(d\vec{F}/dx\), exerted on the horizontal wire segment by the magnetic field of the long wire?

An infinitely long, straight wire lies along the \(y\)-axis and carries a constant current \(I_1\) in the \(+y\)-direction. A separate, straight wire segment of length \(L\) lies in the \(xy\)-plane along the \(x\)-axis from \(x = d\) to \(x = d + L\), where \(d > 0\), and carries a constant current \(I_2\) in the \(+x\)-direction. Which of the following diagrams best represents the direction and relative magnitude of the magnetic force per unit length, \(d\vec{F}/dx\), exerted on the horizontal wire segment by the magnetic field of the long wire?

![A Cartesian coordinate plane with a vertical axis labeled \(y\) and a horizontal axis labeled \(x\), intersecting at an origin marked with an open circle. A thick vertical solid line lies along the vertical axis, with an upward-pointing arrowhead at its top labeled \(I_1\). A thick horizontal line segment lies along the positive horizontal axis, starting at a tick mark labeled \(d\) and ending at a tick mark labeled \(d+L\). A rightward-pointing arrowhead is drawn at the midpoint of this horizontal segment, labeled \(I_2\). A dashed dimension line below the horizontal axis extends from the tick mark \(d\) to the tick mark \(d+L\), labeled \(L\). No other labels, lines, text, or axes appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1790604712-ev0vIX.jpg)

- **A.** Diagram A
- **B.** Diagram B
- **C.** Diagram C
- **D.** Diagram D

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/124908/*