 | Term | Definition |
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electrostatics |
study of the distribution of fixed charges |
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electrification |
the process of electron chargers being added to or subtracted from an object |
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positive electrification |
electrons have been removed from an object, leaving it with a net positive charge |
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negative electrification |
electrons have been added to an object, giving it a net negative charge |
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are electrons infinately moveable |
yes |
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is the earth an electric ground |
yes |
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repulsion |
like charges repel |
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attraction |
unlike charges attract |
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coulomb's law |
inverse square law |
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uncharged particles |
exert no force, and are not acted on by charged particles |
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distribution |
solid conductors have the excess electrons spread over thier outer surface |
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concentration |
electric charges will be concentrated along the sharpest curvature of the conductor |
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laws of elecrostatic force |
force, colomb's law, distribution, concentration, movement |
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movement |
only negative charges move along SOLID conductors |
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electrification b |
when an object is made to have a insufficiency or excess off electrons |
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What conditions cause electrification |
friction, contact, induction |
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friction |
rubbing one object against another, especially during times of low humidity |
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contact |
equalization of charges, static discharge |
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induction |
electrical fields acting on one another without contact |
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example of induction |
balloon vs. wall, high electron balloon causes electrons in wall to disperse in that area |
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coulomb |
the fundamental unit of electric charge |
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electrodynamics |
the study of electric charges in motions: electricity |
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ionic solutions |
neutral atoms with complimentary valences (+1 and -1) are placed in a solution, charged atoms move toward oppositely charged poles |
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conductor |
any substance along which electrons flow easily, good heat conductors are generally good electrical conductors |
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superconductor |
electron flow with no resistance, no electric potential required, must be very cold |
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semiconductor |
william shockley, materials can act as conductors OR insulators, generally composed of silicon and germanium, transistors |
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insulator |
substances that inhibit the flow of electrons, insulators will confine the electron flow to the conductor |
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are voltage and amperage inversly proportional |
yes |
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electrical circuit |
require a close path (if open consider non-working), potential difference must exist for electrons to flow |
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sources of electrical circuit |
batteries, generators, solar converters, atomic reactors |
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current flow |
electrons move from the highest concentration to the lowest |
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direct current |
when all electrons move in the same direction or pulsating |
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alternating current |
when electrons first move in one direction and then reverse and move in the opposite direction |
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current |
the quantity of electrons flowing, measured in amps (I) (A), may indicate the presence of electron flow |
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potential difference |
what makes electrons go forward & back, electric potential, force (strength) with wich electrons travel, also called EMF, measured in volts (V) |
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electric resistance |
the amount of opposition to the flow of electrons |
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qualities of electric resistance |
may be called impedance, measured in ohms. |
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electric resistance influcenced by |
cross-sectional area of the conductor, temperature of the conductor (higher tem=high resistance), length of the wire (longer=higer resistance), increasing resistance decreases electric current |
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electric resistance material |
elements with one electron in the valence shell conduct electricity well, the further the valence shell is from the nucleus (higher shell #) the more efficiently it conducts electricity, conduction band (higher conductivity=less resistance) |
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ohm's law |
voltage across the total circuit or any portion of the circuit is equal to the current times the resistance (V=iR) |
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electric power |
measured in watts (W), one watt= one amp of current flowing through an electric potential of one volt for one second, power loss is proportional to the square of the amperage in a circuit |
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series cicuit |
all circuit elements are connected in a line along the same conductor, electric circuit with the components arranged to provide a single conducting path for current, adding current using devices will cause voltage to drop, any devices in a series circuit that does not work causes the entire circuit to fail |
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parallel circuit |
total resistance is always lower than lowest resistor, circuit elements will bridge the conductor, 2 or more components are connected across 2 common points (bridge) in the circuit to provide seperate conducting paths for current, adding resistors increases amperage & heat |
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types of circuit devices |
circuit breakers, fuses, rheostat (potentiometer) |
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circuit breaker |
too much amperage will cause pop |
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fuse |
too much amperage will melt |
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rheostat |
potentiometer, variable control of amperage, increased resistance allows less current to go to device |
