---
title: "Two long, thin, parallel wires separated by a distance \\(d\\) each carry a current \\(I\\) in the same direction, resulting in an attractive magnetic force per unit length of magnitude \\(F_0\\) between them. The current in both wires is then doubled, and the separation distance between the wires is tripled. What is the new magnetic force per unit length between the wires?"
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url: "https://nerd-notes.com/ubq/118482/"
date_modified: "2026-08-04T08:11:00+00:00"
---

# Two long, thin, parallel wires separated by a distance \(d\) each carry a current \(I\) in the same direction, resulting in an attractive magnetic force per unit length of magnitude \(F_0\) between them. The current in both wires is then doubled, and the separation distance between the wires is tripled. What is the new magnetic force per unit length between the wires?

Two long, thin, parallel wires separated by a distance \(d\) each carry a current \(I\) in the same direction, resulting in an attractive magnetic force per unit length of magnitude \(F_0\) between them. The current in both wires is then doubled, and the separation distance between the wires is tripled. What is the new magnetic force per unit length between the wires?

- **A.** \(\dfrac{2}{3}F_0\)
- **B.** \(\dfrac{4}{3}F_0\)
- **C.** \(2F_0\)
- **D.** \(4F_0\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/118482/*