GCSE Physics

Resistance & Length

Resistance increases with length because the electrons have further to go, so suffer greater collisions with atoms in the material. Look at these wires:
two wires, same diameter, different lengths

Electrons moving through the short wire only feel resistance for a short time compared to the longer one. This means its resistance is less.

Think of the long wire as being a traffic jam on a motorway. It takes ages to get to where you're going. The short wire, however, is like a queue at a roundabout - you soon get where you want to be.

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