Answer
$K = 0.47 \,\text{J}$
Work Step by Step
The charge starts moving from the rest, so the initial kinetic energy is zero. And the final kinetic energy is equal to the potential difference in energy
\begin{gather}
K = U \\
K = q\Delta V \\
K =(q) \frac{\lambda}{2 \pi \epsilon_{o}} \ln \left(\frac{r_{b}}{r_{a}}\right)\\
K = ( 8 \times 10^{-6}\,\text{C} )\frac{3.0 \times 10^{-6}}{2 \pi (8.85 \times 10^{-12})} \ln \left(\frac{4.5}{1.5}\right)\\
\boxed{K = 0.47 \,\text{J}}
\end{gather}
