---
title: "A long, straight horizontal wire carries a constant electric current \\(I\\) to the right. An electron at a location directly above the wire is moving horizontally to the right with velocity \\(\\vec{v}\\). At the same location, a proton is also moving horizontally to the right with velocity \\(\\vec{v}\\). What are the directions of the magnetic force exerted by the wire’s magnetic field on the electron and on the proton at this instant?"
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url: "https://nerd-notes.com/ubq/117373/"
date_modified: "2026-08-04T06:52:00+00:00"
---

# A long, straight horizontal wire carries a constant electric current \(I\) to the right. An electron at a location directly above the wire is moving horizontally to the right with velocity \(\vec{v}\). At the same location, a proton is also moving horizontally to the right with velocity \(\vec{v}\). What are the directions of the magnetic force exerted by the wire’s magnetic field on the electron and on the proton at this instant?

A long, straight horizontal wire carries a constant electric current \(I\) to the right. An electron at a location directly above the wire is moving horizontally to the right with velocity \(\vec{v}\). At the same location, a proton is also moving horizontally to the right with velocity \(\vec{v}\). What are the directions of the magnetic force exerted by the wire's magnetic field on the electron and on the proton at this instant?

![A horizontal straight wire is shown carrying a current labeled I pointing to the right. A point labeled P is located directly above the wire. A horizontal arrow pointing to the right, labeled v, originates from point P, representing the velocity of the charges at that location. No other labels, lines, text, or axes appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1785826319-TAEBaw.jpg)

- **A.** Direction on electron: Toward the wire; Direction on proton: Away from the wire
- **B.** Direction on electron: Away from the wire; Direction on proton: Toward the wire
- **C.** Direction on electron: Into the page; Direction on proton: Out of the page
- **D.** Direction on electron: Out of the page; Direction on proton: Into the page

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/117373/*