• Unit 4: Magnetism

    Now that we have studied electric charges, potentials, and fields, let's look at the effect of moving charges: magnetism. Thales of Miletus set the stage for the scientific exploration of magnetism back in Ancient Greece, when he could only observe magnetism via the behavior of natural magnets, called lodestones.

    Hans Christian Oersted documented the relationship between moving electric charges and magnetism much later, in 1820 when he accidentally discovered that an electric current could deflect a nearby compass needle. James Clerk Maxwell united electrical and magnetic phenomena into four reasonably simple equations, which we know as Maxwell's Equations, 45 years after Oersted made his observation.

    The discovery that electrical currents cause magnetic effects led to the invention of the galvanometer, which we have already encountered as the core component of ammeters and voltmeters.

    Completing this unit should take you approximately 7 hours.

    • 4.1: Magnetic Field

    • 4.2: Magnetic Force on Moving Electric Charges

    • 4.3: Magnetic Field of a Current-Carrying Wire

    • 4.4: Magnetic Materials

    • Unit 4 Assessment