P5 - Electricity In The Home Flashcards
What’s an alternating current?
An alternating potential difference causes current to periodically reverse its direction.
What’s an example of an alternating current (ac)?
Mains electricity is an ac supply.
What’s a direct current?
A direct potential difference causes the current to flow in one direction only.
What’s an example of a direct current (dc)?
A battery is a dc supply.
What colour is the live wire?
Brown
What’s the function of the live wire?
The live wire carries the alternating potential difference from the supply.
What’s the potential difference between the live wire and the earth?
230V
Why is touching the live wire dangerous?
•Touching the live wire and making a connection to earth causes a person to be electrocuted.
•This can be fatal, therefore the live wire is dangerous.
What colour is the neutral wire?
Blue
What’s the function of the neutral wire?
The neutral wire completes the circuit
What’s the potential difference of the neutral wire?
0V
What colour is the earth wire?
Green and yellow stripes
What is the function of the earth wire?
It only carries current if there is a fault. It is a safety feature.
What is the potential difference of the earth wire?
0V
How is electrical power transferred from power stations to consumers?
By using the national grid
What is the national grid?
A system of cables and transformers linking power stations to consumers
What is the purpose of step up transformers?
They increase the potential difference in the transmission lines meaning increasing voltage and decreasing current.
Why is the current lowered in a step up transformer?
Low current means less energy is lost through heating the wire, so is a more efficient way to transfer energy
What is the purpose of step down transformers?
They decrease the potential difference to a safer voltage for use in homes and increase current
