Conclusion: The charges are all on the outer surface of the solution, and the internal potential is 0.

Specific:

First of all, the potential at infinity is defined as zero (no explanation is needed here).

According to gauss theorem: ∮ eds = q/ε 0;

When r

When r> is equal to b, the Gaussian plane contains charge q, then e = q/(4 π ε 0r 2).

Respectively integrating the electric field e to obtain a potential φ;

When r

When r> is equal to b, φ= q/(4ωω0r).