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Physics LibreTexts

22: Source of Magnetic Field

  • Page ID
  • Learning Objectives

    • Understand how to apply the Biot-Savart Law to determine the magnetic field from an electric current.
    • Understand how to apply Amp`ere’s Law.
    • Understand how to model the forces that are exerted on each other by two wires carrying current.
    • Understand how to model a solenoid and a toroid.

    In this chapter, we develop the tools to model the magnetic field that is produced by an electric current. We will introduce the Biot-Savart Law, which is analoguous to Coulomb’s Law in that it can be used to calculate the magnetic field produced by any current. We will also introduce Amp`ere’s Law, which can be thought of as the analogue to Gauss’ Law, allowing us to easily determine the magnetic field when there is a high degree of symmetry.


    How does an electromagnet work?

    1. Current is passed through a magnet, increasing its strength.
    2. Current is passed through a circular coil, creating a magnetic field.