A large negatively charged object is placed on an insulated table. A neutral metallic ball rolls straight toward the object, but stops before it touches it. A second neutral metallic ball rolls along the path followed by the first ball, strikes the first ball, and stops. The first ball rolls forward, but does not touch the negative object. At no time does either ball touch the negative object. What is the final charge on each ball?

The law of conservation of electric charge: The net amount of electric charge produced in any process is zero. or
No net electric charge can be created or destroyed.

Three properties of conductors in static equilibrium.
1. The electric field inside a conductor is zero in the static situation.
2. Any net charge on a conductor distributes itself on the surface.
3. The electric field is always perpendicular to the surface outside of a conductor.

Gauss's law: The total flux summed over any closed surface is equal to the net charge enclosed by the surface divided by eo.