Magnetism Flashcards
Ampere-turn
basic unit of measurement for magnetism
number of turns of wire x current flow
Demagnetized
removal of magnetism from an object
Electromagnets
magnets that rely on electricity to become magnetized
Electron spin patterns
pattern or direction in which electrons spin as they orbit the nucleus of an atom
Flux
magnetic lines of force
Flux density
number of magnetic lines contained in a certain area
Left-hand rule
rule used for determining the polarity of an electromagnet when direction of current flow is known (in a conventional flow circuit)
Lines of flux
lines of magnetic force
Lodestones
natural magnets
Magnetic domains/molecules
section within a magnetic material where atoms are aligned to produce a north or south south polarity
Magnetomotive force
magnetic force produced by current flowing through a conductor or coil
Permanent magnets
magnets that don’t require an external force to maintain their magnetic properties
Permeability
measurement of a material’s ability to to conduct magnetic lines of flux; standard is air w/a permeability of 1
Reluctance
resistance to magnetism
Residual magnetism
amount of magnetism left in an object after magnetizing force has been removed
Saturation
maximum amount of magnetic flux a material can hold
when all the molecules of a magnetic material are lined up
What is the magnetic polarity of the geographic north
south polarity
What is the magnetic polarity of the geographic south
north polarity
Angle of declination
angular difference between the geographic pole and the magnetic pole
T/F: Energy is required to create a magnetic field but no energy is required to maintain a magnetic field
True
List the 3 natural magnets
Iron (Fe)
Nickle (Ni)
Cobalt (Co)
List some ferromagnetic materials
Fe
Ni
Co
Mn (Manganese)
Ferromagnetic
easily magnetized materials
List some paramagnetic materials
Platinum (Pt)
Titanium (Ti)
Chromium (Cr)
Paramagntetic
materials that can be magnetized but not as easily as those that are ferromagnetic
List some diamagnetic materials
Copper (Cu)
Brass
Antimony (Sb)
Diamagnetic
materials that cannot be magnetized
What are the best types of materials to make into magnets and why
ferrites because they are insulators
T/F flux lines surround the entire magnet
true
what is the law of electromagnetism
when an electric current flows through a conductor, a magnetic field is formed around the conductor
what happens to the electromagnetic field once current stops
it no longer exists
air core magnet
EM in which a coil is wrapped around a nonmagnetic material
iron core magnet
EM in which coil is wrapped around magnetic material
which has a stronger magnetic field: air core or iron core
iron core
coercive force
how well a material retains it’s magnetism
magnetomotive force formula
phi x rel
what are ways to demagnetize materials
place object in the field of a strong electromagnet that is connected to an AC circuit
strike it
heat it
Solenoid
when a coil is wrapped around around a material for the purpose of producing an electromagnetic field
Magnetic field is directly or indirectly proportional to it’s ampere-turns
directly (more ampere-turns means a stronger field)
