alternating current (AC)
current in which the flow of charges changes directions several times each second
Coulomb's law
an equation that relates the strength of the force exerted by one charge on another with respect to the distance between them; an inverse square law
direct current
current that moves in one direction; generally produced by batteries or wet cells (DC)
domain
a minute region within a magnet
electric current
the flow of electric charge through a conductor, measured in amperes
electric field
the space around a charge that is influenced by that charge
electromagnet
a solenoid with a core of magnetic material
electromagnetic induction
the creation of an electric current in a circuit exposed to a changing magnetic field
electrostatics
the study of phenomena created by electric charges at rest.
ferromagnetic
a material that is strongly magnetic or magnetized easily
lines of force
imaginary lines that describe the strength and direction of the magnetic field at various positions around the magnet
magnetar
a pulsar with an unusually strong magnetic field
magnetic field
the space surrounding a magnetic through which the magnetic force acts
magnetosphere
the region around a planet occupied by its magnetic field
parallel circuit
a circuit with two or more loops through which the current can flow; each loop has an independent connection to the voltage source
permanent magnet
a magnet made from a ferromagnetic material that does not lose its magnetism after being magnetized
pulsar
a rapidly spinning neutron star
resistance
a measure of how well electric current flows through a material
series circuit
an electric circuit in which resistors are arranged so that they come one after another; the circuit forms one continuous loop
solar wind
the flow of particles from the Sun
solenoid
a coil of current-carrying wire that produces a magnetic field
sunspots
a region on the Sun's surface created by protruding magnetic field lines
temporary magnet
a magnet made from a ferromagnetic material that loses its magnetism quickly