zuai-logo

Induced Currents and Magnetic Forces

Chloe Sanchez

Chloe Sanchez

7 min read

Listen to this study note

Study Guide Overview

This study guide covers magnetic forces on conductors in magnetic fields. Key topics include calculating the magnetic force on induced currents using the formula Fb = âˆĢI(d x B), factors affecting loop force (size, shape, field strength, orientation), and applying Newton's Second Law to analyze loop motion. It also emphasizes the interaction between induced current and magnetic fields, and how to analyze partial field interactions. Practice questions and exam tips are included.

AP Physics C: E&M - Magnetic Forces on Conductors Study Guide

Hey there, future physics pro! Let's break down magnetic forces on conductors. This is a big topic, but we'll make it super clear and easy to remember. Get ready to ace that exam!

Magnetic Forces on Conductors in Magnetic Fields

Introduction

  • Magnetic forces on conductors happen when induced currents flow in a conductive loop. These currents cause charge carriers to move, and they experience forces from pre-existing magnetic fields.
  • The strength of these forces depends on things like the loop's size, the magnetic field's strength, and the relative velocity between the loop and the field.
  • Understanding this is key to analyzing how conducting loops move in magnetic fields and using Newton's second law to predict their behavior.

Force on Conductors in Magnetic Fields

Magnetic Force on Induced Currents

  • Induced currents in conductive loops feel magnetic forces from existing magnetic fields, making the charge carriers move. đŸƒâ€â™‚ī¸

  • Calculate the magnetic force using this equation:

    F⃗B=âˆĢI(d⃗×B⃗)\vec{F}_{B}=\int I(\vec{d} \times \vec{B})

    • F⃗B\vec{F}_{B} is the magnetic force vector.
    • II is the induced current.
    • d⃗\vec{d} is the tiny displacement vector of the conductor.
    • B⃗\vec{B} is the magnetic field vector.
  • Magnetic forces only affect the parts of the loop that are inside the external magnetic field.

  • These forces can cause:

    • Translational acceleration: The loop moves in a straight line.
    • Rotational acceleration: The loop spins or rotates.

Partial Field Interactions

  • The force on a loop depends on:
    • Induced current: How quickly the magnetic flux changes through the loop.
    • Loop resistance: Affects how much current flows.
    • Loop velocity: How fast the...