Two identical metal spheres are charged. Sphere A has a net charge of +7Q. Sphere B has a net charge of -3Q. The spheres are brought together, allowed to touch, and then separated. What is the net charge on each sphere now?

1. Each sphere has a net charge of +4Q
2. Each sphere has a net charge of +2Q
3. Sphere A has +4Q, Sphere B has no net charge
4. Sphere A has +7Q, Sphere B has -3Q
5. Sphere A has -3Q, Sphere B has +7Q

When the spheres are touched the net +4Q charge will spread out evenly over the two spheres. Each sphere will have a net charge of +2Q. This is an example of the Law of Conservation of Charge - the total charge before and after must be the same.