Two of the spheres are brought together so they touch, and then they are separated. Which spheres are they, if the final charge on each one is + 5.0 μC?

The spheres are made of a conducting material probably a metal.

Explanation:

When two spheres are brought in contact with each other and they share the charges equally this means that the sphere are probably made of a metal or some other conducting material. If the spheres are made of same conducting metrical then they must have same size as well to share the charges equally when brought into contact of each other. If the spheres are made of different material then they must not be of the same size in order to share the charges equally. The material with good conductivity must form a smaller sphere and vice-versa to have the equal share of charges upon being separated after a contact.