1. By Joseph Turley and Michael Marrero PERMANENT MAGNETS, MAGNETIC FIELD B, AND THE RELATIONSHIP BETWEEN CURRENT AND B.

2. PERMANENT MAGNETS A permanent magnet is an object that retains its magnetism after being removed from an external field.

3. REMANENCE AND COERCITIVITY Remanence is the amount of magnetization left after the magnet is removed from a magnetic field. Coercitivity is the amount of mgnetivity to revert the magnet to a state of zero magnetization.

4. MAGNETIC FIELD Magnetic field is the mathematical description of the relationship between magnetic influence and electric current. Magnetic fields are produced by the movement of electric charges.

5. UNITS ASSOCIATED WITH MAGNETIC FIELDS The Tesla is the unit associated with magnetic fields 1 Tesla is equal to 1 Ns/Cm. For smaller magnetic fields they use Gauss 1 Tesla = 10,000 Gauss

6. RELATIONSHIP BETWEEN MAGNETIC FIELD AND CURRENT All moving charges produce a magnetic field. Magnetic field lines are made of concentric circles. More current means greater magnetic field.

7. CONCEPT QUESTION What happens when a ferromagnetic material is magnetized with a magnetic field pointed in the opposite direction of which it was magnetized originally?

8. CONCEPT QUESTION Given all other things equal, which would have the greater magnetic field – A wire with a current of 10 amperes running through it? Or a wire with 20 Amperes of current running through it?