An infinitely long uniform solid wire of radius $a$ carries a uniform dc current of density $\overrightarrow{j}$.
A hole of radius $b$ (b < a) ia now drilled along the length of the wire at a distance $d$ from the center of the wire as shown below.
The magnetic field inside the hole is
- uniform and depends only on $d$
- uniform and depends only on $b$
- uniform and depends only on both $b$ and $d$
- non uniform