# Shared Flashcard Set

Chp 24 physics
Magnetisim
33
Physics
10/15/2011

## Additional Physics Flashcards

Term
 Stones found in Greece which had properties that attracted pieces of iron.
Definition
 lodestones.
Term
 is the attraction of unlike magnetic poles for each other and the repulsion between like magnetic poles.
Definition
 magnetic force
Term
 what is the source of magnetic force.
Definition
 motion of charged particles, usually electrons.
Term
 if a magnet has alternating north and south poles it has a long magnetic distance
Definition
 false.
Term
 like poles =opposite poles=
Definition
 -repel-attract
Term
 electric charges can be isolated while magnetic poles can not.
Definition
 -true
Term
 negatively charged electrons and positive electrons are________________
Definition
 entities by themselves.
Term
 region of magnetic influence around a magnetic pole or a moving charged particle.-ex)when you sprinkle iron dust around a magnet you get this effect.
Definition
 magnetic field
Term
 a magnetic field is produced by the motion of ____________.
Definition
 electrical charge
Term
 where is the motion in a common magnet bar
Definition
 in the electrons of the atoms in the magnet.
Term
 what is a chief contributor to magnetism.
Definition
 electron spin
Term
 a pair of electrons spining in the same direction =a pair of electrons spining in the opposite direction=
Definition
 -stronger magnet-magnet works against each other.
Term
 -the magnetic field of an individual iron atom is so strong that interactions among adjacent atoms cause-what is the name for this.
Definition
 -large clusters of them to line up with one another.-magnetic domains
Term
 can magnetic domains of atoms alighn themselves.
Definition
 yes
Term
 when someone put a magnet to a iron nail and removes the magnet the alignment will remain.
Definition
 false.-but if the permentant magnet is very strong then the nail may retain some magnetisim.
Term
 how are permanent magnets made
Definition
 -placing iron in strong magnetic fields.-stroking an iron with a magnet
Term
 heating or droping a magnet will make it stronger.
Definition
 false.
Term
 since a moving charge produces a magnetic field, it ______________.when compasses surround a magnetic pole this happens.
Definition
 follows the charges of the magnetic field.
Term
 magnetic fields will__________ if more coils are present.
Definition
 increase.
Term
 a current carrying coil of wire is an_____________.
Definition
 electromagnet.
Term
 how do ind. magnets gain more power
Definition
 by having iron in their coils.
Term
 -the most powerful electromagnets are called______________ which large amounts of electrical current flows with ease.-is there heat loss as energy moves through these_____
Definition
 -superconducting electromagnets.-no
Term
 a charged particle at rest will not interact with a __________. but if the charged particle is ____ the magnetic charge is evident.
Definition
 -static magnetic field-moving
Term
 the direction of force is always perpendicular to the ___________ and to the velocity of the charged particle.
Definition
 -magnetic field lines
Term
 the force that acts on a moving charged particle does not act along the line that joins the sources of interaction but, instead, acts perpendicularly to both_________________.
Definition
 magnetic field and electron beam.
Term
 a current of charged particles moving through a magnetic field also experiences a _______________.
Definition
 deflecting force.
Term
 a sensitive current indicating instrument is called a _______________.
Definition
 galvonmeter.
Term
 -in a motor the current is made to change direction every time the coil makes a ________________.-the current in the loop flips direction with each half turn and __________________
Definition
 -half rotation.-continuous rotation results.
Term
 the current in a motor is reversed during each half revolution by means of _____________________.
Definition
 -stationary contacts on the shaft.
Term
 what do scientist believe cause earths magnetic field.
Definition
 moving charges looping around within earths molten interior.
Term
 -protons, alpha particles, and other atomic nuclei striped of electrons, and high energy electrons make up what kind of rays which hit earth.-what happens when these hit electronics-do these cause the northern and southern lights
Definition
 -cosmic rays-causes them to fail-true
Term
 the idea of living creatures such as pigeons and bees having a capability called geomagnetism is impossible.
Definition
 false, animals do have this to find their way around.
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