QUESTION !
A solid non-conducting sphere carries a total charge Q = -3 mC distributed evenly throughout.
It is surrounded by an uncharged conducting spherical shell.
- Inside the conductor, we know the field: E = 0
- Since E = 0 on this surface, the total enclosed charge must be 0
- Therefore s1 must be positive, to cancel the charge -Q
- Select a Gaussian surface inside the conductor
- By the way, to calculate the actual value: s1 = Q / (4 p r12)