TABLE OF CONTENTS The important properfies of time independent static magnetic fields will be reviewed in this chapter. A magnetic field is significantly different from an electric field because it is impossible to isolate a Norths Pole from a South Pole of a magnet and treat them as independent magnetic-charges as -we were able to with electric fields. The magnetic field arises when electrical charge is in motion. Electrical charges in motion create an electrical current and this current creates a magnetic field. Several procedures to calculate the magnetic field from a current will be described. There will be a magnetic force exists between two current-carrying elements. Certain materials will have a profound impact on the characteristics of the magnetic fields. Finally, the electrical circuit element called the inductance and the topic of magnetic circuits will be introduced.
Imagine that a wire is connected to a battery and a resistor as shown in Figure 3-1 a. The battery is a chemical source that provides particles with a positive charge and a negative charge. In the metallic wire, the ions are stationary and a portion of the electrons are free to move. Benjamin Franklin gave us the convention that the direction of the flow of the current, however, should be in the direction of the motion of the positive particles. Between the two terminals of the battery there will be an electric field that will accelerate the electrons. Since the conductivity of a wire is significantly greater than the...
