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Electricity (Chapter 20)

Terms in this set (45)

Electrical Charge
a property that causes subatomic particles such as protons and electrons to attract or repel each other
How is a net electrical charge produced?
an excess or shortage of electrons
Coulomb (C)
SI unit for electric charge, 1 coulomb = 6.24 x 10^18 electrons
What determines whether charges attract or repel?
like charges repel, opposite charges attract
Electric Force
the force of attraction or repulsion between electrically charged objects
Electric Field
the effect an electric charge has on other charges in the space around it
What are the two factors that affect the strength of an electric field?
the amount of charge that produces the field and the distance from the charge
Static Electricity
the study of the behavior of electric charges, including how charge is transferred between objects
What are the three methods of charge transfer?
by friction, contact, and induction
Law of Conservation of Charge
the total charge in an isolated system is constant
Induction
transfer of charge without contact between materials
How does static discharge occur?
when a pathway in which charges can move forms suddenly
How does electric force depend on the amount of charge and the distance between charges?
directly proportional to the net charge on each object and inversely proportional to the square of the distance between them
Electric Current (I)
the continuos flow of electric charge
Ampere/Amp (A)
SI unit for current, 1 amp = 1 coulomb/second
What are the two types of current?
direct current and alternating current
Direct Current (DC)
flow of electric charge in only one direction
Alternating Current (AC)
flow of electric charge that regularly reverses its direction
Electric Conductor
a material in which charge can flow easily
Electric Insulator
a material in which charge cannot flow easily
Resistance
opposition to the flow of charge in a material
Ohm
SI unit for resistance
What variables affect the resistance of a material?
thickness, length, temperature
The more the distance, the ____ the resistance. The greater the temp, the ____ the resistance.
The more the thickness, the ___ the resistance.
more, more, less
Superconductor
a material that has almost zero resistance when it is cooled to low temperatures
What causes charge to flow?
the wire must be connected in a complete loop that includes a source of electrical energy
Potential Difference
the difference in electric potential energy between two places in an electric field (voltage)
Volts (V)
unit for potential difference, volts = joules/coulombs
Battery
a device that converts chemical energy to electrical energy
Ohm's Law
V = I x R
How is voltage related to resistance and current?
increasing the voltage increases the current. keeping the same voltage and increasing the resistance decreases the current
Electric Circuit
a complete path through which charge can flow
Circuit Diagram
shows one or more complete paths in which charge can flow
What is the direction of current?
the direction in which positive charges flow
Series Circuit
charge has only one path that it can flow through
Parallel Circuit
an electrical circuit with two or more paths through which charges can flow
What is the difference between parallel and series circuit?
if one element stops functioning in a series, everything stops. if one element stops in a parallel, the rest operates
Electric Power
the rate at which electrical energy is converted to another form of energy
How do you calculate electric power?
P = I x V
What is the equation for electrical energy?
E = P x t
What are 5 safety devices used with electric current?
correct wiring, fuses, circuit breakers, insulation, and grounded plugs
Fuse
prevents current overload in a circuit
Circuit Breaker
a switch that opens when current in a circuit is too high
Grounding
the transfer of excess charge through a conductor to Earth
Multimeter
a device used to measure current
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