domestic electricity + energy resources Flashcards
what r the 2 types of current
alternating - this current is constantly changing direction. it i supplied in main electricity
direct current - this current only travels in one direction supplied by cells and batteries
how much volts is mains electricity and whats the frequency of uk mains
mains electricity is 230V. the frequency of UK mains electricity is 50Hz
what colour is live wire
brown
what colour is the fuse
yellow
what colour is the earth wire
green and yellow
what colour is the neutral wire
blue
what are the 3 types of wire
earth.live and neutral
whats the live wire
live wire (brown) provides alternating potential difference at 230V
whats the neutral wire
neutral wire (blue) - completes the circuit,carrying current away at 0V
whats the earth wire
earth wire (green + yellow) - also at 0V and will carry current away from the device in case of a fault
theres a fuse between live wire and the live pin if to much current flows what happens
the fuse breaks and stops the flow of current
if the electrician touches the live wire he will receive an electric shock explain why
electricians body is 0V
live wire is connected to a metal device at 230V
electrician touches live so large potential difference between him and the live (230V)
current flows though him to ground causing an electric shock
how does the earth wire protect u
the earth wire protects you, by carrying this current to “earth” instead of it passing through you
when current flows what moves around the circuit
when current flows charges (electrons) move around a circuit
whats power
power is the rate of energy transferred in a given period of time
whats the national grid
the national grid is a network of cables and transformers which supply the UK with electricity. in order to transmit a certain power, the electricity has a high voltage and a low current. This means less energy is wasted as heat,making the national grid more efficient
what are insulators
they dont allow the movement of charge e.g.plastic
what do conductors do
allow the movement of charge e.g. metals
whats static charge and give example
a buid up of charge that does not move.Can be either positive or negative. Static charge can build up on insulators when they are electrically isolated e.g. when duster is rubbed on rod. Electrons transfer from rod to duster
duster becomes negative rod becomes positive
explain what happens when polythene rod is rubbed w duster
when polythene rob is rubbed w duster,electrons are removed leaving the rod positivelt charged. when the rod is moved towards the water, the electrons in the water are attracted towards the edge. now the positive rod attracts the negative side of the water causing it to bend
whats an electric field
an electric field is created around any electrically charged object. electric fields are represented by lines
whats sparking (static shocks)
when charge builds up an object there is a potential difference between the object and the earth (0 vaults). the large potential difference creates an electric field between the object + the earth . this electric field removes electrons from air molecules,turning the air into a conductor this means the charge can flow through the air
whats a transformer
a transformer is a device used in the national grid to change the potential difference of an electrical supply.
