# Shared Flashcard Set

## Details

Chapters 24,25, and 26
N/A
39
Physics
04/28/2011

Term
 lodestone
Definition
 naturally occuring magnetic rocks
Term
 when is a magnet polarized
Definition
 when it has a north and south pole
Term
 ferromagnetic
Definition
 materials that can be converted into a magnet
Term
 where do magnetic fields exist
Definition
 in areas with magnetic force
Term
 magnetic flux
Definition
 the number of magnetic field lines passing through a surface
Term
 where is a magnetic field strongest
Definition
 at the poles
Term
 where do magnetic field lines leave
Definition
 the north pole
Term
 where do magnetic field lines enter
Definition
 the south pole
Term
 current carrying wires produce a
Definition
 magnetic pole perpendicular to the direction of the current
Term
 first right hand rule
Definition
 the direction of the current is the direction of the magnetic field
Term
 solenoid
Definition
 a long coiled wire which increases total strength
Term
 domain
Definition
 the alignment of electrons of multiple atoms in a group of atoms
Term
 when does a material become a magnet
Definition
 when domains align
Term
 what does a motor convert
Definition
 electrical energy to kinetic energy
Term
 galvanometer
Definition
 a device used to measure small currents
Term
 a changing magnetic field can produce a
Definition
 current
Term
 electromagnetic induction
Definition
 the process of generating a current through a circuit
Term
 electromotive force
Definition
 the influence that makes the current flow from higher to lower potential difference
Term
 electric generator
Definition
 consists of a number of wire loops around an iron core that rotates between a north and south pole of a magnet
Term
 armature
Definition
 the wire coil of an electric motor
Term
 in the U.S. utilities use a frequency of
Definition
 60Hz
Term
 In the U.S. we use a voltage of
Definition
 120V
Term
 Lenz's law predicts
Definition
 the direction of current flow
Term
 Lenz's states that
Definition
 An induced current is always in such a direction as to oppose the motion or change causing it
Term
 Lenz's law causes the armature of a generator to be
Definition
 more difficult to turn
Term
 sensitive balance
Definition
 uses lenz's law to stop oscillation
Term
 eddy currents
Definition
 generated in a metal and produces a magnetic field that acts to oppose the motion that caused the current
Term
 self inductance
Definition
 the induction of emf in a wire carrying changing current
Term
 In the changing current due to self inductance a back-emf is created which makes the potential of the top of the wire
Definition
 more negative than the bottom of the wire
Term
 transformers
Definition
 devices that use self inductance to increase or decrease AC voltages
Term
 what did JJ Thompson discover?
Definition
 the charge to mass ratio of an electron
Term
 isotope
Definition
 differing forms of an atom which have different masses but the same chemical properties
Term
 mass spectrometer
Definition
 a device used to determine the charge of mass ratios of certain ions
Term
 a changing electric field produces a changing magnetic field
Definition
 electric charges aren't necessary
Term
 elecrtomagnetic wave
Definition
 a combined electric and magnetic field that travels through space at right angles to one another
Term
 dielectric
Definition
 a nonconducting material
Term
 piezoelectricity
Definition
 the application of AC voltage onto a section of quartz crystal which results in sustained oscillations
Term
 x-rays
Definition
 high frequency Em waves that are created when high energy electrons strike the metal target inside a cathode ray tube
Term
 right hand rule
Definition
 the direction of a magnetic force on a moving charge is always perpendicular to the magnetic field and the velocity of the charge
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