Domestic electricity

What are 2 differences between the electricity supply from the mains and the supply from a battery? Tick 2 boxes.

• A battery has a higher potential difference than the mains.

• The current from the mains is alternating current whereas a battery supplies direct current.

• The current coming out of the mains is always higher than a battery.

• The mains has a greater voltage than a battery.

What is the frequency of the mains?

• 230V

• 130V

• 50Hz

• 230Hz

In the order shown in the picture from left to right what are the names of the different coloured wires?

• earth, neutral, live

• neutral, earth, live

• earth, live, neutral

• live, earth, neutral

What is the potential difference of the live wire?

• 230V

• 50V

• 12V

• 0V

What is the potential difference of the neutral wire?

• 230V

• 50V

• 12V

• 0V

Which statement best describes a fuse?

• A device that controls the current running through an appliance.

• An adaptor that transforms the voltage in the circuit into current.

• A safety feature where a piece of wire of a specific thickness melts when the current is too high breaking the circuit.

• A safety feature where a piece of wire of a specific thickness melts when the voltage is too high breaking the circuit.

What advantages do circuit breakers have over fuses? Tick 2 boxes.

• They are triggered faster.

• They are less expensive to buy.

• They use up less electricity.

• They do not need to be replaced each time they are triggered.

Which scenario most necessitates the earth wire?

• An appliance with a plastic case.

• An appliance with a metal case.

• An appliance with a 12V power supply.

In a plug, which wire is the fuse wire connected to?

• The live wire

• The neural wire

• The earth wire

• None of the above

The resistance of an appliance is 50 ohms. It is plugged into the mains. Using the formula V=IR determine what fuse should be connected to the appliance.

• 3A

• 5A

• 7A

• 13A