Problem 3.147

A long cylinder with uniformly charged surface and crosssectional radius $a=1.0 \mathrm{~cm}$ moves with a constant velocity $v$ $=10 \mathrm{~m} / \mathrm{s}$ along its axis. An electric field strength at the surface of the cylinder is equal to $E=0.9 \mathrm{kV} / \mathrm{cm}$. Find the resulting convec. tion current, that is, the current caused by mechanical transfer of a charge.