2.4 Understand that 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

Definition of resistance: How easy or difficult it is for electrons to flow through a wire. The more difficult it is, the higher the resistance.

A resistor makes it more difficult for electrons to flow through the wire. The kinetic energy that moves them along is transferred to heat energy and so the overall temperature increases.

HOW IS THIS USEFUL?!
It can be used in hairdryers or heaters :)