Mains Electricity Flashcards
What is the brown/red wire?
The live wire
What is the potential difference of the live wire in the UK?
230v
Is mains electricity alternating or direct current?
Alternating
Where is the live wire connected to in the plug?
The fuse
Why is the live wire fatal if touched?
Current will flow through the person and into the earth which will go through the heart and stop it potentially.
What is the blue wire?
The neutral wire
what is the potential difference of the neutral wire?
0v compared with the live wire
What is the green wire called?
Earth wire
What does the earth wire do?
It is the safety wire to stop the appliance from become live by taking the energy into the ground.
What does the fuse symbol look like?
A rectangle with a line.
How does the earth wire do to stop an appliance from becoming live.
An appliance with a metal case may become like if the live wire is damaged for some reason. The earth wire is connecting the appliance to the ground and it takes the current into the ground. Then the fuse will melt and will shut off the current.
What is the national grid made of -> simple
Transformers and high voltage cables
What is the problem with the national grid? How can it be avoided?
A lot of energy is lost from the power cable due to the resistance of the wires. It is also lost through conversion into heat energy.
It can be avoided by putting power stations near homes but it upsets people who want to a nice view. Another way it may be avoided is using transformers
How do transformers remove the loss of power into the environment?
Electricity goes through the step up transformer this makes potential difference increase to several hundred thousand volts. This then travels as far as it can before it goes too close to housing. It then goes through a step down transformer (230v) it then goes into houses.
We increase the potential difference because less energy is lost when potential difference is high.
