Problem 3.266

A straight round copper conductor of radius \(R=5.0 \mathrm{~mm}\) carries a current \(I=50\) A. Find the potential difference between the axis of the conductor and its surface. The concentration of the conduction electrons in copper is equal to \(n=0.9 \cdot 10^{23} \mathrm{~cm}^{-3}\)