P4 supplying electricty Flashcards
what does a battery provide
direct current
DC
what does mains electricity provide
alternating current
AC
what colour is the earth wire
green and yellow
what does the earth wire do
safety
has a 0V
only carries voltage if there is a fault
what colour is the neutral wire
blue
what does the neutral wire do
completes circuit
what colour is the live wire
brown
what does the live wire do
carries voltage
how much potential difference does the live wire carry
230V
why is plastic used to coat wires and plug case
Because plastic is an electrical insulator
what is the fuse connected to
the live wire
what is the live wire connected to
the fuse
what does the fuse do
keeps appliance safe
if voltage goes over what is safe fuse will break
SHORT CIRCUIT
what is a short circuit
when the fuse breaks and disconnects live wire from the mains
what metal is used inside wires
copper
why is copper used inside wires
good conductor
cheap
bends easily
what is the national grid
network of cables and transformers that link homes ext
what is a transformer
device that changes potential difference
how much PD do cables in national grid transfer
up to 400,000 volts
what is the frequency of mains electricity
50 hz
what is the voltage of mains electricity
230 v
what is one watt equal to
1 joule per second
ohmic conductor
when voltage is directly proportional to current in a conductor
it obeys Ohm’s law
