A solid conducting sphere 60 mm in radius carries a charge of 5.3nC. A thick conducting spherical shell of outer radius 120 mm and inner radius 100 mm carries a charge of -4.0 nC and is concentric with the sphere.
1. Compute the surface charge density on the surface of the solid sphere.
2. Compute the surface charge density on the inner surface of the thick shell.
3. Compute the surface charge density on the outer surface of the thick shell.