Electricity Flashcards
What is the difference between the neutral wire and the earth wire when switched on?
0 V
The person should not touch the metal case because there is a _____________. So it gives the person an electric shock.
current in the person
Why is it safe to touch the metal casing when it is connected with the earth wire instead of live wire?
The charge flows through the earth wire, so the resistance of the earth wire is much less than the person.
What is the difference between current supplied by mains supply and battery?
The mains electricity is an alternating current that constantly changes direction.
The battery is a direct current which only flows in one direction.
Why is touching the live wire dangerous? (4)
The potential of the live wire is 230 V, a person’s potential is 0V.
There is a large potential difference between the live wire and person.
The current can pass through the person’s body.
Why are step-up transformers used in the National Grid?
To increase the voltage across the cables, to decrease the energy losses in the cables.
This will increase the efficiency of the transmission.
What does transformer 2 do in the National Grid?
It decreases the potential difference for domestic use.
