Answer
$i=2.08\times 10^9A$
Work Step by Step
We know that:
$\mu=i A$
$\mu=i \pi r^2$
We re-arrange the formula:
$i=\frac{\mu}{\pi r^2}$
We plug in the known values to obtain:
$i=\frac{8\times 10^{22}}{3.1416\times (3500\times 10^3)^2}$
$i=2.08\times 10^9A$
