SHOW HANDWRITTEN WORK

$(30)$ See example $28\mathrm{.}8$ in the textbook. A long, cylindrical, imperfect

conductor with radius R carries a total current I $($Fig$.28\mathrm{.}20).$ The

current is uniformly distributed over the cross$-$sectional area of the

conductor. Find the magnetic field magnitude B produced by the

conductor

$($a$)(10$ points$)$ inside at r$=($R$)/(4)$ and

$($b$)(10$ points$)$ outside at r$=4$R

$($c$)(10$ points$)$ at r$=0$

Use I, R$,$ and any other symbols, numerical or otherwise, for your

answers as needed.