iGCSE Physics Mains electricity

Which is the unit of current?

• volts

• amps

• watts

• joules

Which is the unit of voltage?

• volts

• amps

• watts

• joules

Complete the sentence: The ring mains consist of three wires: live, neutral and

• Mars

• ground

• earth

• mains

Complete the sentence: The role of the neutral wire in a mains circuit is

• to carry current from the power station to your home.

• to provide a path of least resistance to the ground.

• to resist all current flow.

• to complete the circuit so that current can flow.

Complete the sentence: The role of the earth wire in a mains circuit is

• to protect the user should the appliance develop a fault.

• to carry current from the power station to your home.

• to resist the flow of current.

• to provide an alternating current.

Which of the following is an insulator used in plugs?

• copper wiring

• brass pins

• plastic casing

• fixing screws

Where should a switch be placed in a mains circuit?

• connected to the earth wire

• connected to the live wire

• connected to the neutral wire

• anywhere in the circuit

Wires in a heating element are said to have high resistance. Why is this?

• All the energy carried by the current is delivered to the appliance.

• Energy is transferred to the wires as the current passes through so they heat up.

• To prevent current flowing and causing the heating element to break.

• None of the above.

Which of the following statements defines the term double insulated?

• The appliance is insulated against energy transfer and electricity.

• The appliance has an earth wire and a plastic casing.

• There are two layers of insulation surrounding the cable.

• The casing is made from an insulator such as plastic.

Complete the following sentence: Electrical power is defined as

• the energy in the circuit.

• the rate of flow of charge.

• the rate of energy transfer.

• the number of electrons in the circuit.