current is the measure of the flow of electrons around the circuit, measured in amps by an ammeter
potential difference is the driving force of the flow of electrons and is measures in volts by a voltmeter
resistance is everything at opposes the flow of electrons and is measured in ohms
an alternating current changes direction
a direct current doesn't change dircetion
is a series circuit what is shared?
potential difference
is a series circuit what is the same everywhere?
current
a series circuit only has one loop
in a parallel circuit what is shared?
current
in a parallel circuit what is the same in each component?
potential difference
a parallel circuit has more than one loop
in a parallel circuit, the loops with a higher resistance have lower current
the more components in a parallel circuit the lower the resistance
in a series circuit the sum of the resistance in each component is the total resistance
how does the neutral wire complete the circuit?
it carries the current away
what is the potential difference of the neutral wire?
0v
what is the potential difference of the earth wire?
0v
what does the earth wire do?
stops the appliance becoming live if the live wire touches the casing as it provides an alternating pathway for current to flow
what colour is the earth wire?
green and yellow
what colour is the neutral wire?
blue
what colour is the live wire?
brown
what is the potential difference of the live wire?
230v
where does the live wire get the current from?
mains supply
why is each wire made of copper?
conduct electricity
why does a step up transformer increase the voltage?
so current is kept low so less energy is lost as heat to the surroundings
what does a step up transformer increase?
voltage to 400,000
what does a step down transformer do?
decreases voltage to 230v for safety
when does electricity peak?
in the late afternoon
what is a surge?
a sudden increase in current
what can surges cause?
fires, damage appliance, electrical shock
why is a high pressure dangerous?
risk of explosion
what do fuses and circuit breakers do?
break the circuit if the current is too high
what is the a fuse connected to?
live wire
what does a fuse do if a high current passes through it?
melts
why can fuses be costly?
have to be replaced after each use
why are circuit breakers better than fuses?
don't have to be replaced after each use
what can someone do to prevent electrical shock?
-use earthing (an earth wire)
-double insulating appliances (less likely to need an earth wire)
how do fossil fuels and nuclear power stations work?
generate thermal energy with turns water into steam which turns a turbine then generates kinetic energy which can be converted into electrical energy and sent across the national grid