Question

Find the resistivity of the material of a metallic conductor of length 2 m and area of cross-section 1.4 × 10^-6 m². The resistance of the conductor is 0.04 ohm.

Answer 1

Given: Resistance R = 0.04 ohm

Area of cross section A = 1.4 × 10^-6 m² 

Length l = 2 m

Using the formula,

R = ${\displaystyle \rho \frac{l}{\text{A}}}$

Resistivity ρ can be calculated as

P = ${\displaystyle (\text{R}\times \text{A})/l}$

So resistivity = (0.04 × 1.4 × 10^-6 m²)/2m

= 2.8 × 10^-8 Ohm-meter