---
title: "Two long, straight, perpendicular wires lie in the xy-plane along the x-axis and y-axis. Each wire carries an electric current of equal magnitude \\(I\\), with current flowing in the \\(+x\\)-direction along the x-axis and in the \\(+y\\)-direction along the y-axis. Four points—\\(P\\), \\(Q\\), \\(R\\), and \\(S\\)—are located in the four quadrants, each at a distance \\(d\\) from both wires, as shown in the figure. Which of the following correctly ranks the magnitude of the net magnetic field \\(B\\) at these four points?"
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url: "https://nerd-notes.com/ubq/116328/"
date_modified: "2026-08-03T12:23:28+00:00"
---

# Two long, straight, perpendicular wires lie in the xy-plane along the x-axis and y-axis. Each wire carries an electric current of equal magnitude \(I\), with current flowing in the \(+x\)-direction along the x-axis and in the \(+y\)-direction along the y-axis. Four points—\(P\), \(Q\), \(R\), and \(S\)—are located in the four quadrants, each at a distance \(d\) from both wires, as shown in the figure. Which of the following correctly ranks the magnitude of the net magnetic field \(B\) at these four points?

Two long, straight, perpendicular wires lie in the xy-plane along the x-axis and y-axis. Each wire carries an electric current of equal magnitude \(I\), with current flowing in the \(+x\)-direction along the x-axis and in the \(+y\)-direction along the y-axis. Four points—\(P\), \(Q\), \(R\), and \(S\)—are located in the four quadrants, each at a distance \(d\) from both wires, as shown in the figure. Which of the following correctly ranks the magnitude of the net magnetic field \(B\) at these four points?

![A two-dimensional Cartesian coordinate system showing two long, thin, perpendicular straight wires lying along the x-axis and y-axis. The wire along the x-axis carries a current I in the positive x-direction, indicated by an arrow pointing right labeled I. The wire along the y-axis carries an equal current I in the positive y-direction, indicated by an arrow pointing up labeled I. Four points are labeled in the four quadrants, each at a distance d from both axes: point P at (d, d) in Quadrant I, point Q at (-d, d) in Quadrant II, point R at (-d, -d) in Quadrant III, and point S at (d, -d) in Quadrant IV. No other labels, lines, text, or axes appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1785759808-6O2adA.jpg)

- **A.** \(B_P = B_Q = B_R = B_S\)
- **B.** \(B_P = B_R > B_Q = B_S\)
- **C.** \(B_Q = B_S > B_P = B_R\)
- **D.** \(B_Q > B_P = B_R > B_S\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/116328/*