20.2 - electric current and ohms law Flashcards
(23 cards)
what is an electric current
the continuous flow of electric charge
what is DC charge?
charge only flows in one direction in a direct current
what is AC current?
charge flows, regularly reversing direction in an alternating current
SI unit of current?
ampere (A) or amp
what is resistance?
opposition to the flow of charges in a material
SI unit of resistance?
ohm
electrons flow more quickly through a thick/thin wire?
thick wire
what type of wire is resistance greater in?
a longer wire
as temp increases, resistance ____________.
increases
what is a superconductor?
a material that has almost 0 resistance when cooled to lower temperatures
what is voltage?
the force that pushes electrons through a circuit (aka potential difference)
with voltage, electrons flow from ________ to _________ potential energy.
higher to lower
SI unit for voltage?
volts (V)
what is an electric circuit
a complete path in which charge can flow
what is a series circuit?
a circuit in which charge only has 1 path
what happens if 1 bulb burns out in a series circuit?
the circuit becomes open
what happens to the resistance if you add bulbs in a series circuit?
the resistance increases; each bulb shines less brightly
what is a parallel circuit?
a circuit where there are multiple paths a charge can flow through
SI unit for power?
watts (W)
what prevents current overload in a circuit?
a fuse
what is a circuit breaker?
a switch that opens when current in a circuit is too high
what can prevent short circuits?
insulation
what is grounding?
transfer of excess charge though a conductor to earth
