MAGNETIC FORCES Magnetism Fields. M AGNETISM  Law of magnetism states that like magnetic poles repel and unlike poles attract each other

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M AGNETIC F IELD  Magnets exert forces that seem to originate from the magnetic poles, and they can affect another magnetic object even without contact.  The ancient Greeks called this effect “ action at a distance.”  Field lines are “lines of force”

Text of MAGNETIC FORCES Magnetism Fields. M AGNETISM  Law of magnetism states that like magnetic poles...

MAGNETIC FORCES Magnetism & Fields M AGNETISM Law of magnetism states that like magnetic poles repel and unlike poles attract each other. M AGNETIC F IELD Magnets exert forces that seem to originate from the magnetic poles, and they can affect another magnetic object even without contact. The ancient Greeks called this effect action at a distance. Field lines are lines of force M AGNETIC F IELD L INES M AGNETIC F IELD Magnetic field lines have the following properties: magnetic field lines are continuous loops that never cross inside the magnet, the magnetic field lines point from the south pole to the north pole outside the magnet, the magnetic field lines point away from the north pole toward the south pole the closeness of the lines represents the strength of the magnetic field (the closer the lines are together, the stronger the magnetic field) if the field lines are parallel, the magnetic field is uniform M AGNETIC F IELD L INES M AGNETIC F IELD 1 Tesla = 1 T = 1 N / (A*m) D OMAIN T HEORY A material that is made from a magnetized material and creates a magnetic field is a permanent magnet. Some materials become magnetized when they are placed in an external magnetic field. These are called ferromagnetic materials, and include iron, nickel, and cobalt. D OMAIN T HEORY The outermost electrons of the atoms of ferromagnetic materials create tiny magnetic fields in each atom. The magnetic fields of adjacent atoms can align to reinforce each other, forming small regions, or domains, with intense magnetic fields. M AGNETISM AND C URRENT Early scientists believed that electricity and magnetism were related, but the link between them eluded scientists until 1820 Oersteds principle: When a current moves through a conductor, it creates a magnetic field. R IGHT H AND R ULE It was shown that when a current flows in a straight conducting wire, the magnetic field forms a circular pattern that is perpendicular to the wire S OLENOID (C OIL ) The magnetic field of a solenoid is similar to a bar magnet S OLENOID (C OIL ) M AGNETISM

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