An electrical appliance has a plastic outer casing and is designed with double insulation. This appliance does not require an earth wire.
What is the main function of double insulation in this appliance?
to reduce the electrical resistance of the appliance so that it works more efficiently
to prevent the user from receiving an electric shock if an internal live wire comes loose
to ensure the appliance can be plugged into any socket regardless of the voltage
to complete the circuit so that electric current can return to the main power supply
135 exam-style questions on CIE IGCSE Physics Electrical safety, covering Electrical safety. Each one has a worked solution and a mark scheme showing where the marks go.