Besides temperature, experimental results shows that the resistance (R of a given conductor) also depends on the composition and size.
Resistance, R is found to be:
- directly proportional to its length, L
- inversely proportional to its cross-sectional area
- dependent on the type of material
From experimental results, we can show that:
$R = \rho \frac{L}{A} $
,where
R = resistance in ohm ($\Omega $)
A = cross-sectional area of conductor in metre2 (m2)
L = length of conductor in metre (m), and
$\rho $ = resistivity of material in ohm-metre ($\Omega m$)
For the similar lengths and material,
Thinner wires have higher resistance than thicker wires.
For similar thickness and material,
Longer wires have higher resistance than shorter wires.
