Walker, Halliday & Resnick — Current and Resistance: Problem 20

20 Figure 26-21 gives the electric potential \( V(x) \) along a copper wire carrying uniform current, from a point of higher potential \( V_s = 12.0\text{ }\mu\text{V} \) at \( x = 0 \) to a point of zero potential at \( x_s = 3.00\text{ m} \). The wire has a radius of \( 2.20\text{ mm} \). What is the current in the wire?