Resistance of a Wire vs. Diameter and Length - Electricity Physics GCSE

This physics tutorial explains how the resistance of a wire depends on its diameter.
The larger the diameter, the more paths there are for charge carriers (electrons) to flow down, and so the easier it is for them to flow.
Resistance is defined as how much potential difference (think 'electrical push' or 'pressure difference') is needed to make 1 amp of current flow.
So a high resistance means you need a high potential difference just to get 1A to flow.
A long length of wire will have a high resistance. The electrons continue to move and flow just as quickly, but they will need to start with a lot more energy at the beginning of the wire and they will then transfer this into thermal energy as they go through the wire.
Potential difference is actually the energy difference of each coulomb (a 'bag' of electrons) as they enter a component compared to when they leave the component.
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