Question

A power transmission line is made of copper 1 .80cm in diameter. Find the resistance of one mile of this line.

Answer 1

Gives

Diameter of copper wire (d)=1.80cm

Cooper wire resistivity$\rho=1.72\times10^{-8}\Omega m$

Radius (r)=0.90cm $=0.90\times10^{-2}meter$

Length (L)=1mile=1609.34meter

Cross section area of copper wire (A)=$πr^2$

$A=3.14\times{0.009}^2$

$A=25.434\times10^{-5}m^2$

Resistance

$R=\frac{\rho l}{A}\rightarrow(1)$

Put value in eqution (1)

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

$R=\frac{1.72\times10^{-8}\times1609.34}{25.434\times10^{-5}}$

$R=0.1088\Omega$