Resistivity and Conductivity

Resistivity:

In SS1, we discussed Factors Affecting the Electrical Resistance of a Conductor :

These factors are:

• The temperature of the conductor.
• The length of the conductor.
• The cross-sectional area of the conductor.
• The nature of the material of which the conductor is made.

Combining all factors shows that resistance (R) is directly proportional to the length (l) of a conductor and inversely proportional to the area (A) and is given by the expression:

R = \( \scriptsize \rho \normalsize \frac{l}{A} \)

𝜌 = a constant called resistivity of a material

Resistivity is the resistance, per unit length, of a conductor of unit cross-sectional area.

𝜌 = \( \frac{RA}{l} \)

When A = 1, and l = 1 we have that 𝜌