electricity & magnetism

william gilbert

noticed similarities between magnetism and electricity

de magnete

1600 - book that summarized everything known abt magnetism and electricity

electricity

pos & neg charge

like charge = repel, unlike charge = attract

charged objects set up electric field of forces

rubbing electrifies

magnetism

north & south seeking poles

like poles = repel, unlike poles = attract

magnetic objects set up magnetic fields of force

rubbing magnetizes

magnetic field

vector field (arrows) to determine the distribution of magnetic force within & around magnet

allow magnets to attract objects without touching

domain theory of magnetism

every atom has magnetic property & each electron has magnetic field

caused by spin & movement around nucleus

electrons act like magnetics

ferromagnetic

materials strongly attracted to magnets

refrigerator magnets, iron, nickel, cobalt

regions where orientation of magnetic field of every atom is lined in one direction

paramagnetic

some attraction to magnets

mixed with iron

aluminum, platinum

diamagnetic

not attracted to magnets, sometimes repelled

bismuth, copper, gold

geo south

magnetic north

geo north

magnetic south

hans christian oersted

1819 - magnetic field exists around current carrying wire

important discovery established electromagnetism

basic principle of electromagnetism

when electrons move thru a conductor, a magnetic field is created

right hand rule

determines direction of magnetic field

thumbs up: thumb - direction of current, fingers - direction of magnetic field

electromagnets

coil of wire (solenoid) w/ iron core

strong magnetic field when strong current is introduced

magnetic field magnetizes iron core, making north & south poles

generator

converts mechanical energy to electrical energy

motors

converts electrical energy to mechanical energy

electromagnetic induction

movement of magnet/coil through each other

magnet has to move for there to be an electrical current