(b) Mains electricity

Understand how the use of insulation, double insulation, earthing, fuses and circuit breakers protects the device or user in a range of domestic appliances

Understand why a current in a resistor results in the electrical transfer of energy and an increase in temperature, and how this can be used in a variety of domestic contexts

Know and use power = current × voltage, P = IV, and apply it to selecting appropriate fuses.

Use energy transferred = current × voltage × time, E = IVt.

Know the difference between mains electricity being alternating current (a.c.) and direct current (d.c.) being supplied by a cell or battery