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Cole Enriched Physics - Current Electricity

Terms in this set (67)

Electricity is the flow of electric current in wires, motors, light bulbs, and other inventions.
What is electricity?
A) Electric current is similar to a current of water, but electric current is not
visible because it usually flows inside solid metal wires.
B) Electric current can carry energy and do work just as a current of water can.
C) Electric current can carry great deal of energy.
Characteristics of electricity
A continuous loop of conductors that allows electricity to flow. There must be some "power" source for the electricity (like a battery).
What is a circuit?
A circuit with no breaks.
- A light bulb will light only when it is part of a closed circuit. Opening a switch or disconnecting a wire creates a break in the circuit and stops the current.
What is a closed circuit?
A circuit with breaks.
- A light bulb that is broken stops the path of electricity creating an open circuit. If a battery is dead, it also creates an open circuit.
What is an open circuit?
One path for electric current to flow. Any break in the circuit stops current from moving.
What is a series circuit?
More than one path for current. A break in part of the circuit only eliminates flow from that loop of the circuit.
What is a parallel circuit?
Circuit diagrams
What are electrical drawings called?
A material that allows electricity to flow freely through it because the atoms' electrons are loosely held. (Ex: metal)
What is a conductor?
A material that prevents electricity from flowing through it because the atoms' electrons are tightly held.
What is an insulator?
A fundamental property of matter that can be + or - or zero (neutral). It is what causes electrically charged objects to attract or repel.
What is a charge?
Current is the flow of electrically charged particles.
What is a current?
Amps (A)
What is current measured in?
Current flows from the positive end of a battery through the circuit to the negative end of the battery.
How does current flow?
A device used to measure current.
What is an ammeter?
Must be a part of the circuit to allow current to flow through the ammeter.
How does an ammeter work?
The difference in electrical potential or electric potential energy.
What is voltage?
Volts (V)
What is voltage measured in?
A) Voltage difference means there is energy that can be used to do work or was used to do work
B) Voltage provides energy to push the charge in the conductors
C) Voltage is the difference in electrical potential
energy in two parts of a circuit
D) Current always flows from positive (high potential energy) to negative (low potential energy)
E) Voltage is directly related to current
F) Voltage is the cause of current
Characteristics of voltage
Measures voltage. Must be connected in parallel (around components).
What is a voltmeter?
A) Source of voltage
B) Use chemical energy to create a voltage difference between two terminals
C) Current is moved by voltage. The current carries energy to electrical devices.
Characteristics of a battery
- Bulb voltage = battery voltage
- The battery supplies voltage (difference in electrical potential energy)
- The bulb transfers energy
- All voltage/electric potential energy is transformed before the current returns to the battery
Voltage of battery and bulb
- Total bulb voltage = bulb 1 + bulb 2 = Battery voltage
- All voltage/electric potential energy is transformed before the current returns to the battery
Voltage of bulbs in series
- Each branch (path) gets the total voltage from the battery
Voltage of bulbs in parallel
- Each branch (path) gets the total voltage from the battery
- Bulbs in series must split that voltage
Voltage of bulbs in compound circuit
How strongly an object opposes current flow.
What is resistance?
Electrical device that uses the energy carried by electric current in a specific way.
What is a resistor?
Ohms (Ω)
What is resistance measured in?
A) Resistance opposes current
B) Resistance is inversely related to current
C) Wires have a resistance that is practically zero
D) Light bulbs or any device that transforms energy provide resistance
Characteristics of resistance
RT = R1 + R2 + R3 ...
Resistance series equation
(1/RT) = (1/R1) + (1/R2) + (1/R3) ...
Resistance parallel equation
I = V/R
Ohm's Law equation
Voltage: Total voltage from the battery is split among the resistors in series

Current: Current is the same everywhere

Resistance: Total resistance is equal to the sum of the resistances in the circuit
Circuit rules: SERIES
Voltage: Voltage in each branch is equal to the total voltage in from the battery

Current: Total current in the battery is equal to the sum of the currents in each branch

Resistance: Total resistance (equivalent resistance) is equal to inverse of the sum of the inverse resistances
Circuit rules: PARALLEL
1) Whenever there is electric current, a magnetic field is formed.
2) Whenever there is a moving magnetic field, electric current is produced.
Electric current & magnetic field characteristics
Device that converts kinetic energy (motion) into electrical energy (current).
What is an electric generator?
Device that converts electrical energy (current) into kinetic energy (motion).
What is an electric motor?
Parallel
In which case will there be more current in each of three lamps -- if they are connected to the same battery in series or parallel?
Parallel
In which case will there be more voltage across each lamp?
The total resistance of the circuit increases.
A circuit contains one light bulb and a battery. What happens to the total resistance in the circuit if you replace the one light bulb with a string of four identical light bulbs?
Through
Does charge flow through a circuit or into a circuit?
Battery
A _________ provides voltage to a circuit.
Voltage
_______ is the difference in the amount of energy carried by current at two points in a circuit.
Volt
The __________ is the unit for measuring voltage.
Resistor
A light bulb, motor, or speaker acts as a ___________ in a circuit.
Ohm
The __________ is the unit for measuring resistance.
Ohm's Law
_________ explains the relationship between current, voltage, and resistance in a circuit.
Resistance
__________ is the measure of how strongly a material resists current.
Current
The greater the resistance in a circuit, the less the _________.
Current
_________ is what flows and carries power in a circuit.
Closed circuit
A ___________ has a complete path for the current and contains no breaks.
Ampere
The unit for current is the _________.
Positive, negative
The direction of electric current in a circuit is away from the _____________ end of the battery and toward the ____________ end.
The same as that through the light bulb
The current through the battery is _______.
Increases
As more lamps are put into a parallel circuit, the overall current in the power source ____________.
Decreases
As more lamps are put into a series circuit, the overall current in the power source ___________.
Less resistance
Compared to the resistance of two resistors connected in series, the same two resistors connected in parallel have ___________.
A
What does adding batteries do to the voltage in a circuit?
A) Adding batteries increases the voltage.
B) Adding batteries decreases the voltage.
C) Adding batteries has no effect on the voltage.
C
What determines total voltage in a circuit?
A) The number of bulbs.
B) The type of circuit (series or parallel)
C) The number of batteries
D) All of the above
C
Voltage is...
A) A quantity of charge moving past a point every second
B) Opposition to current
C) A difference in electrical potential energy
D) A rate of energy transfer
B
When two bulbs are connected in parallel to a battery, the electrical resistance that the battery senses is
A) More than the resistance of either lamp.
B) Less than the resistance of either lamp.
C) None of these
A
When two bulbs are connected in series to a battery, the electrical resistance that the battery senses is
A) More than the resistance of either lamp.
B) Less than the resistance of either lamp.
C) None of these
D
What determines the current coming from the batteries?
A) The number of bulbs.
B) The type of circuit (series or parallel)
C) The number of batteries
D) All of the above
B
As more lamps are put into a series circuit, the overall current in the power source
A) Increases
B) Decreases
C) Stays the same
A
As more lamps are put into a parallel circuit, the overall current in the power source
A) Increases
B) Decreases
C) Stays the same
B
Compared to the resistance of two resistors connected in series, the same two resistors connected in parallel have
A) More resistance
B) Less resistance
C) The same resistance
A
Current is ....
A) a quantity of charge moving past a point every second.
B) opposition to current.
C) a difference in electrical potential energy.
D) a rate of energy transfer
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