ABSTRACT
This chapter looks at the various unit conventions currently in use in magnetism and discusses methods for calculating magnetic fields. A magnetic field is produced whenever there is an electrical charge in motion. The axial component of the magnetic field on the axis of the coils can be calculated from the Biot-Savart law. The Biot-Savart law can be used to determine the magnetic field at the center of a circular coil of one turn with a radius of meters, carrying a current of amperes. Ampere’s law and the Biot-Savart law can be shown to be equivalent. The field due to a steady current flowing in a long current-carrying conductor is considered. The unit of magnetic induction has been defined in terms of the force exerted on a current-carrying conductor. The lines of magnetic induction always form a closed path since we have no direct evidence that isolated magnetic poles exist that would act as sources and sinks of magnetic flux.
