Magnetic Fields and Forces

In this module, magnetic forces and fields are studied. The sequence of the discussions is magnetic forces on charge and on current wire, then magnetic field computations using Biot-Savart law, and followed by the introduction of Ampere’s law. In terms of the techniques for calculating magnetic field strength, the emphasis is on applications of Ampere’s law. Magnetic field in and around a straight current wire, magnetic field at the center of a circular current wire, and magnetic field inside a solenoid are carefully analyzed in this module.

Introduction

The theme of this module is magnetism. The module begins with a brief review of commonly occurring phenomena attributable to magnetism. Then a discussion about the effects of magnetic field on charges and currents, and the vector cross product (aka the right-hand rule) is introduced in this context.  Biot-Savart law is followed in the development of the magnetic field strength around a straight current, as well as at the center of a current loop. This derivation work demonstrates the usefulness of Biot-Savart law, at the same time its tedious side, which is a perfect jumping-off point to talk about Ampere’s law next. The focus of the last few units of the module is on applications of Ampere’s law.

This module consists of a sequence of 9 videos with 2 step-by-step solved examples and 6 self-assessment questions. It is expected that the course instructor, will supplement the module with additional questions and possibly one laboratory exercise.

Prerequisites

Before starting this module, it will be helpful to be familiar with:

• magnets,
• Electric current,
• Cross product of two vectors.