2. Definition : A magnetic field is a force field which surrounds either a magnet or a wire carrying an electric current and will act upon, without contact, another magnet or current carrying wire Like the other fields we have studied we represent magnetic fields diagrammatically using field lines or lines of magnetic flux Plotting Compass

3. We name the ends of a magnet “the poles”. (North and & South). More correctly they should be referred to as the “North seeking pole” and “South seeking pole” The arrows on a magnetic field line represent the path which a “tiny free north pole” would take Like poles repel each other Unlike poles attract each other

4. The Earth has a magnetic field just like a giant magnet. The geographic North pole has a South magnetic pole associated with it (Since a north seeking pole of a magnet will point towards it) Earth Dipole

5. Watch terminology!!! At the geographic North pole there is a magnetic pole which we can refer to as “Magnetic North”. However it is a South pole! Watch the field lines!

6. Wires carrying a magnetic current produce a magnetic field “Maxwell’s corkscrew rule” can be used to establish the direction of this field. Note the current direction is the direction of “conventional current” positive to negative