A conducting rod moving across a magnetic field develops a motional electromotive force.
Difficulty
Intermediate
Read time
5 min
Prerequisites
Basic algebra, consistent units, and the stated model assumptions
Source
OpenStax, College Physics 2e, §23.3 (Paul Peter Urone and Roger Hinrichs)OpenFormulaGraph equation reference; FormuLab adaptation details and license are provided below.
Adapted from OpenFormulaGraph, under CC BY 4.0.
FormuLab adapted wording, notation, applicability conditions and topic placement, and expanded the numerical check into a worked example. The textbook section reference was corrected.
A conducting rod moving across a magnetic field develops a motional electromotive force. The simple product applies when rod direction, velocity, and magnetic field are mutually perpendicular.
| Symbol | Meaning | Units |
|---|---|---|
| Voltage (emf) | ||
| Magnetic Field | ||
| Conducting rod length | ||
| Rod speed |
Estimate induced emf across a rod.
Relate conductor motion and magnetic flux effects.
A 2.00 m conducting rod moves at 3.00 m/s perpendicular to itself and a uniform 0.500 T magnetic field. Find the emf magnitude.
OpenFormulaGraph equation reference; FormuLab adaptation details and license are provided below.
Adapted from OpenFormulaGraph, under CC BY 4.0.
FormuLab adapted wording, notation, applicability conditions and topic placement, and expanded the numerical check into a worked example. The textbook section reference was corrected.
Assumptions
FormuLab is a study reference. Verify formulas, units, assumptions, and course-specific conventions before relying on them.
© 2026 FormuLab. All rights reserved.