Answer
$J = 5.41\times 10^7~A/m^2$
Work Step by Step
In part (a), we found that the current is $i = 1530~A$
We can find the current density:
$J = \frac{i}{A}$
$J = \frac{i}{\pi~r^2}$
$J = \frac{1520~A}{(\pi)(3.00\times 10^{-3}~m)^2}$
$J = 5.41\times 10^7~A/m^2$
