Question

Determine the length of a copper wire that has a resistance of 0.172 ? and cross-sectional area of 7.85 × 10-5 m2. The resistivity of copper is 1.72 × 10-8 ?·m.

Answer 1

Answer:

Length of copper wire, l = 785 meters

Explanation:

Given that,

Resistance of the copper wire, R = 0.172 ohms

Area of cross section, $A=7.85\times 10^{-5}\ m^2$

Resistivity of copper, $\rho=1.72\times 10^{-8}\ \Omega-m$

The resistance of a wire is given by :

$R=\rho\dfrac{l}{A}$

$l=\dfrac{RA}{\rho}$

$l=\dfrac{0.172\ \Omega\times 7.85\times 10^{-5}\ m^2}{1.72\times 10^{-8}\ \Omega-m}$

l = 785 meters

So, the length of the copper wire is 785 meters. Hence, this is the required solution.