Unit 4 Day 1 – Magnetic Fields Produced by Electric Currents
• Magnets
• Magnetic Fields Surrounding Magnets
• Magnetic Fields Produced by Electric Currents
Magnets• Certain materials exhibit ferromagnetic
properties, ie: they are surrounded by a magnetic field
• Magnetic materials are: iron, nickel, cobalt, & gadolinium (and their alloys)
• Magnets consists of two ends called poles, referred to a north and south
• The magnetic field surrounding a magnet forms a closed loop through the magnet, in the direction from north to south
Magnetic Fields Surrounding Magnets
• A compass is used to determine the direction of a magnetic field.
• A compass needle always points away from the north magnetic pole
Magnetic Field Surrounding the Earth
• The earth consists of a magnetic field. • Note: The earth’s north-magnetic pole is at the south
geographic pole
Magnetic Field Between Two Magnetic Poles
• Magnetic fields between two wide poles of a magnet are nearly uniform with only slight fringing at the edges
• Magnets always consists of two poles
• Magnetic mono-poles do not exist in nature and have never been observed
Magnetic Fields produced by Electric Currents
• In 1820 Hans Christian Oersted found that a compass placed close to a current carrying conductor will deflect the needle
Magnetic Fields produced by Electric Currents
• An electric current produces a magnetic field around a wire. The direction of the field follows the Right hand Rule #1