G 6.20 - How to demagnetize something (it's what de-Gauss button does on a CRT computer monitor)

G 7.3 - relation between capacitance and resistance
G 7.4 - resistance between two cylinders
G 7.7 - sliding bar on rails in B-field

Bonus questions

G 7.39 - conductivity between two pipes

Examples class problems

G 7.1 - resistance between concentric spherical metal shells
G 7.8 - square loop near wire
G 7.10 - rotating square loop