Force on a Wire

Part of the Electricity and Magnetism section of Coddy's Physics journey. Lesson 44 of 51.

A straight wire of length L carrying I through a field B feels

$F = BIL\sin\theta$

θ between the wire and B.

Its direction: the right-hand rule, fingers along the current.

A wire in a field

Challenge

A horizontal wire $0.5\ \mathrm{m}$ long with a mass of 20 g carries $4\ \mathrm{A}$ through a horizontal field that points into the page, and it floats: the magnetic force holds it up. How strong is the field $B$ ?

Try it yourself

Solve for $B$

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Electricity and Magnetism

1Electric Charge and Force

Electric Charge Coulomb's Law Several Charges Recap - Charges in a Line

4Charged Conductors

The Charged Sphere Connecting Spheres Recap - Beam Between Plates

7Real Batteries

Internal Resistance The Variable Resistor Ammeters and Voltmeters Recap - Flashlight

10Magnetic Fields

Magnets and Magnetic Fields Field of a Wire Loops and Solenoids Recap - Electromagnet

2The Electric Field

The Electric Field Field of Several Charges The Uniform Field A Charge in a Uniform Field Recap - Stopping a Proton

5Capacitors

The Capacitor Combining Capacitors Changing a Capacitor Recap - Camera Flash

8Kirchhoff's Laws

The Junction Rule The Loop Rule Solving Two Loops Recap - Charging a Battery

11Magnetic Forces

Force on a Moving Charge Circles in a FieldForce on a WireTwo Parallel Wires Recap - Current Balance

3Energy and Potential

Electric Potential Energy Electric Potential Field and Potential Recap - Accelerating Ions

6Current and Resistance

Current and Voltage Resistance and Ohm's Law Series and Parallel Electric Power Recap - Fairy Lights

9Capacitors in Circuits

A Capacitor in a Circuit Charging a Capacitor Discharging a Capacitor Recap - Defibrillator

12Induction

A Rod Moving in a Field Magnetic Flux Faraday's Law Lenz's Law Recap - Generator