Electricity Test Flashcards
What is a conductor?
a material that allows electrons to flow/ change positions
Ex. copper, aluminum
What is an insulator?
a solid, liquid or gas that resists or blocks the movements of electrons
Ex. rubber, wood
What is a voltmeter and what does it measure? How do you connect a voltmeter to a circuit?
a device used to measure potential difference/ voltage
it is connected in parallel (across the device being measured)
What is an ammeter and what does it measure? How do you connect an ammeter in a circuit?
a device used to measure electric current
it is connected in series
What is an ohmmeter and what does it measure?
a device used to measure resistance
Voltage
measures the difference in energy per charge between 2 points
the “force” that pushes electrons to go through a circuit
Unit: V
Symbol: V
Resistance
an opposition to the flow of charge
Unit: Ω
Symbol: R
Current
the flow of electrons
(the number of charges that pass by a particular point each second)
Unit: A
Symbol: I
What are the 4 factors that affect resistance?
- Material
- Temperature
- Length
- Thickness
Material
Silver has the least resistance but is very expensive to use in wires. Most conducting wires are made from copper
Temperature
as the temperature of the wire increases, its resistance increases and its conductivity decreases. A colder wire is less resistant than a warmer wire
Length
Longer wires offer more resistance than shorter wires. If the wire doubles in length, it doubles in resistance
Thickness
Wider wires offer less resistance than thinner wires. If the wire doubles in width, its resistance is half as great. Conducting wires that carry large currents need large diameters to lessen their resistance
Explain how cross-sectional area affects resistance:
the larger the cross-sectional area, the easier it is for electrons to flow. therefore, it will have lower resistance.
Series Circuit
a circuit that allows electrons to flow along only 1 path
