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} $


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.

Back To Current Electricity (O Level)

Back To O Level Topic List

Sharing is caring:
Mini Physics

Administrator of Mini Physics. If you spot any errors or want to suggest improvements, please contact us.

Leave a Comment