43 terms

Physics Pre-AP: Chapters 17 & 18

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current (d1)
movement of electric charge
current (d2)
rate at which electric charges pass through a given area
charge carriers
positive and negative charges in motion
conventional current
the current of a positive charge that would have the same effect as the motion of the charge carriers
test hint
a difference in electric potential maintains current in a circuit
potential difference
voltage, push that keeps electricity flowing
resistance
the opposition to the flow of current in a conductor
test hint 2.0
resistance is constant over a wide range of potential differences (ohm's laws)
materials that follow ohm's law are said to be
ohmic
materials that do not follow ohm's law are said to be
non-ohmic
diodes
LED - light admitting diodes
resistor
a simple electrical element that provides a specified resistance
superconductor
have zero resistance below a certain temperature called the critical temperature
meissner effect
because electric currents produce magnetic effects, current in a superconductor can be used to float a magnet in the air over a superconductor
chemical energy stored in a battery is continuously converted to the electrical energy of the charge carriers. as the charge carriers move through a conductor, this electrical energy is converted to internal energy (heat, light, etc) due to
collisions between the moving charges remaining material in the circuit elements
electric power (1)
the rate at which charge carriers do work
electric power (2)
electric power is the rate at which charge carriers convert potential energy to nonelectrical forms of energy
potential difference (d)
the change of potential energy per unit of charge
joule heating (I^2r loss)
the conversion of electrical energy to internal energy in a resistant material
not
copper, gold, and silver are conductors, but ___ super conductors.
schematic diagram
a representation of a circuit that uses lines to represent wires and symbols to represent components.
electric circuit
a set of electrical components connected such that they provide one or complete paths for the movement of charges.
circuit diagram
a schematic diagram for a circuit is sometimes called a
load
any element or group of elements in a circuit that dissipates energy. (thing in a circuit that uses the energy)
closed circuit
there is a closed looped path for electrons to follow. (on- turned on circuit)
open circuit
without a complete path, there is no charge flow and therefore no current. (off- turned off circuit)
short circuit
closed circuit without a load - very little resistance (no bulb or resistor)
emf
the energy per unit charge supplied by a source of electric current
electro motive force
emf
terminal voltage
the potential difference across the battery's terminal
equal
the potential increase across the battery must _____ the potential decrease across the load, because energy is conserved
series
describes two or more components of a circuit that provide a single path for the currents
equivalent resistance
the total resistance of the circuit
parallel
a wiring arrangement that provides alternative pathways for the movement of charge
equals
charge is conserved so the sum of the currents in each bulb ____ the current delivered by the battery
why is the equivalent resistance for a parallel group of resistors always less than the smallest resistance in the group?
because of the reciprocal relationship
no
do parallel circuits require all elements to conduct?
120
what voltage do most outlets in North America provide?
no (2)
is the voltage in NA the same as the voltage in other continents?
series, parallel
in homes fuses or circuit breakers are wired in _____ to numerous outlets, which are wired together in _____
fuse
a small metallic strip that melts if the current exceeds a certain value
circuit breaker
triggers a switch when current reaches a certain volume
why is the current in a fuse or circuit breaker the same as the total current in the circuit?
because it is wired in series to the house