Electricity Flashcards
what is the definition of current
the flow of charge
what is a direct current
a current flowing in 1 direction
where is a dc produced?
cell or battery
what is an alternating current?
a current which changes direction 50 times a second.
where is a ac produced?
mains or a power pack
when the voltage is high what happens to the current?
it is also high
when the resistance is high the current is ___.
low
if there is more resistance___ voltage is needed.
greater
the v/i graph for a resistor shows both values in ___ proportion
direct
in a parallel circuit, as we add more components the current ____ and resistance ___
increases, decreases
in a parallel circuit resistance is ____ than in a series circuit
lower
when more resistors are added in a parallel the total resistance goes ___
down
what does a v/i graph look like for a diode
completely flat until it spikes upwards
what does a v/i graph look like for a filament lamp?
it curves all over the place
what can happen to a fuse in a plug if the current is to high
it melts
which wire works with a fuse?
earth
put these things in order in national grid.
step up transformer
step down transformer
domestic/commercial power
power station
transmission
power station
step up
transmission
step down
domestic/commercial power
what does a step up transformer do to the current
lowers it significantly as it increase pd and the power stays the same.
what is the pd of domestic power
230V
what is the pd of commercial power
10-30KV
what does the earth wire act as?
a safety by only carrying current in an emergency
what is the pd of the neutral wire
0V
Why is plastic used as insulation of a plug?
it is a good insulator
how can a plug short circuit?
the live wire and neutral wire touch.
