Question

the copper track on a printed circuit board is made from copper foil 35um thick. the width of the track is 0.16cm and the resistivity of copper is 1.69x10^-8ohms. what is the resistance of 1cm of track?

Answer 1

Resistance of wire(R) = $\rho \frac{l}{A}$

Here, $\rho$ is the resistivity of the wire

l is the length of the wire

A is the cross section area of wire

Given,

$\rho$ = 1.69 x 10^-8 ohm m

l = 0.01 m

A = (1.6 x 10^-3)(3.5 x 10^-5)

= 5.6 x 10^-8 m²

So,

R = (1.69 x 10^-8)$\frac{10^6}{5.6}$

= 3.018 x 10^-3 ohm