Question

A wire has a diameter of 5mm, length 50m, resistivity 3.2 x 10^-8 ohmsm. What is the resistance of the wire?

Answer 1

We can find the resistance of the wire from the formula:

$$R=\rho\dfrac{l}{A},$$ $$R=3.2\cdot10^{-8}\ \Omega\cdot m\cdot\dfrac{50\ m}{\pi\cdot\dfrac{(5\cdot10^{-3}\ m)^2}{4}}=0.081\ \Omega.$$