B) mains electricity

What is the difference between mains electricity being alternating current (a.c.) and direct current (d.c.) being supplied by a battery

An alternating current (a.c.) is one that continuously changes its direction, going back and forth around a circuit.

A direct current (d.c.) is one that is steady, constantly going the same way around a circuit, from positive to negative.

Risk of using electricity in a kitchen

Water

Understand how the use of fuses protects the device or user in a range of domestic appliances

Stop the flow of current by melting if the current is too high.

So it protects sensitive components and people because if the components function at too high temperatures it can cause a fire.

Why does a current in a resistor result in the electrical transfer of energy and an increase in temperature

how this can be used in a variety of domestic contexts

Electricity, in metals, is caused by a flow of electrons.

As electrons flow through the metal, they collide with ions, making them vibrate more (as they lose some energy, giving it to the ions) so the metal heats up

used in many electric heaters, including electric ovens, some types of electric hob, toasters, kettles and old fashioned light bulbs.

use of insulation and double insulation

insulation and double insulation prevent people from touching exposed wires and getting shocks

use of earthing

Earth connected to appliance
It becomes live
Provides low resistance path to the earth
Fuse is then broken
So circuit switches off

use of circuit breakers

Circuit breakers again break the circuit if current is too high.