Physics Y9 Electricity Flashcards
what is potential difference measured in
volts (V)
what is current measured in
amps (A)
what is resistance measured in
ohms (Ω)
what is the formula for resistance
resistance (R) = potential difference (V) / current (I)
what happens if a voltmeter is in series
block current completely
a voltmeter has a very low/high resistance
high
an ammeter has a very low/high resistance
low
what happens if an ammeter is in parallel
it creates a short circuit
how is total resistance calculated in a series circuit (2 ways)
measure the voltage across battery or add up the resistance of each component
does resistance in a wire change with current
no
what is the formula for potential difference
potential difference (V) = energy transferred (E) / charge flow (Q)
what is energy transferred measured in
joules (J)
what is charge flow measured in
coulombs (C)
what is the formula for charge flow
charge flow (Q) = current (I) * time (t)
an electric current is a flow of ______
charge
voltmeters should be placed in ______
parallel
ammeters should be placed in ______
series
what is an ammeter used for
measuring current
what is a voltmeter used for
measuring potential difference
what is a variable resistor used for
allowing the current to be varied
what is this symbol: ⏛
fuse
what is an electrical conductor
a material which allows a current to flow through it when a voltage is established across it
what is a fuse used for
stopping the flow of electricity if something is wrong
why are parallel circuits used for house lights
so they can be switched on and off seperately
what is a fuse
a piece of wire that melts when it gets too hot
what is a resistor used for
limiting the current in a circuit
why does a conductor conduct
it is a material that has a mobile charge carrier
what is a battery
two or more cells connected together
what happens if an ammeter is in series
it works
what happens if a voltmeter is in parallel
it works
