gcsescience.com                                       46                                       gcsescience.com

Electricity

The Resistance of Wires - Length.

Does the Resistance of a Wire depend on its Length?

The resistance of a wire changes if its length changes.
This makes sense if you consider that there are a
number of collisions between the electrons and the ions
when electricity flows through 1 metre of a wire.
There are twice as many collisions when electricity
flows through 2 metres and 3 times as many
collisions when electricity flows through 3 metres etc.

If we plot this on a graph
we get a straight line relationship as shown below.

As long as the material, thickness and the temperature
of a wire stays the same then the resistance
is directly proportional to the length of the wire.
Doubling the length of the wire will double the resistance.

     Links      Electricity      Mains      Revision Questions