Problem 3.159

Two long parallel wires are located in a poorly conducting medium with resistivity $\rho$. The distance between the axes of the wires is equal to $l$, the cross-section radius of each wire equals $a$. In the case $a \ll l$ find: (a) the current density at the point equally removed from the axes of the wires by a distance $r$ if the potential difference between the wires is equal to $V$; (b) the electric resistance of the medium per unit length of the wires.