Question

Calculate the resistance of copper wire with a diameter of 2.5968 mm having a length of 1000 m at 20°C.

Answer 1

Resistivity of copper at 20$^0 C$ is = 1.68 $\times 10^{-8} \Omega m$

Resistance = Resistivity $\times \frac{Length}{Area}$

R= $\rho \frac{L}{A}$

A= $\pi r^2$ = 3.142 $\times (\frac{ 2.5968\times 10^{-3}}{2})= 5.2969\times 10^{-6} m^2$

R= 1.68 $\times 10^{-8} \times \frac{1000}{ 5.2969\times 10^{-6}}$ = 3.1717 $\Omega$

R= $3.1717 \Omega$