The resistance (R) of a conductor,
- is directly proportional to its length (l). i.e., R ∝ l
- is inversely proportional to its cross-sectional area (A). i.e., \(R\propto\frac1A\)
- The resistance of the conductor depends upon the nature of the material.
- It changes with the temperature (T)
The corresponding relation which gives the relationship among the above-mentioned factors is given by: \(R=\rho\frac lA\). where,
ρ is the resistivity (or the specific resistance) of the conductor.
Moreover, if α be the temperature coefficient of the material of the wire, then the resistance of the wire at t2° C is given by \(R_2=R_1\left[1+\alpha\left(t_2-t_1\right)\right]\)
Where R1 is the resistance of the wire at t1° C.
Hence: l, A, ρ, α, are the factors on which the resistance of a conductor depends.