---
title: "A student measures the magnetic field magnitude \\(B\\) at various perpendicular distances \\(r\\) from a long, straight wire carrying a steady current \\(I\\). The student plots \\(B\\) as a function of \\(\\dfrac{1}{r}\\) and fits a line of best fit to the data, as shown in the graph. Based on the graph, what is the current \\(I\\) in the wire?"
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url: "https://nerd-notes.com/ubq/121246/"
date_modified: "2026-08-23T04:59:00+00:00"
---

# A student measures the magnetic field magnitude \(B\) at various perpendicular distances \(r\) from a long, straight wire carrying a steady current \(I\). The student plots \(B\) as a function of \(\dfrac{1}{r}\) and fits a line of best fit to the data, as shown in the graph. Based on the graph, what is the current \(I\) in the wire?

A student measures the magnetic field magnitude \(B\) at various perpendicular distances \(r\) from a long, straight wire carrying a steady current \(I\). The student plots \(B\) as a function of \(\dfrac{1}{r}\) and fits a line of best fit to the data, as shown in the graph. Based on the graph, what is the current \(I\) in the wire?

![A 2D Cartesian graph with gridlines. The vertical axis is labeled B (\mu\text{T}) with major tick marks and gridlines at 0, 10, 20, 30, 40, 50, and 60. The horizontal axis is labeled 1/r (\text{m}^{-1}) with major tick marks and gridlines at 0, 10, 20, 30, 40, and 50. Exactly five data points appear as solid circular dots near coordinates (10, 12), (20, 24), (30, 36), (40, 48), and (50, 60). A single solid straight best-fit line starts at the origin (0, 0) and extends upward through the point (50, 60). No other labels, lines, text, or axes appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1787461140-q3GWqz.jpg)

- **A.** \(0.95 \text{ A}\)
- **B.** \(1.2 \text{ A}\)
- **C.** \(3.0 \text{ A}\)
- **D.** \(6.0 \text{ A}\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/121246/*