Final answer:
Metal spheres conduct electricity, allowing charge to redistribute evenly when they touch. Two negatively charged spheres will share their total charge upon contact and have equal charges when separated. The behavior of spheres, whether they move away or towards each other, indicates whether their charges are like or opposite.
Step-by-step explanation:
When two charged metal conducting spheres come into contact, the electrons will redistribute themselves in such a way that the charge is evenly divided between the two spheres. This is because metal conducts electricity, allowing the free flow of electrons, and the electrostatic forces cause repulsion between like charges. If we take Sphere A with a charge of −5 nC and Sphere B with a charge of −3 nC and bring them together, they touch and share the total charge of −8 nC. Upon separation, each sphere would have a charge of −4 nC.
For instance, if each electron has a charge of approximately −1.6 x 10⁻¹¹C, we can calculate the number of electrons corresponding to the charge on each sphere after they have been brought into contact and then separated. You would find that each sphere ends up with 2.5 x 10⁴ electrons following the redistribution of the charge (since −4 nC corresponds to 2.5 x 10⁴ electrons).
When analyzing the interaction between a positive and an unknown charge sphere, if the left (unknown charge) sphere swings towards the positively charged right sphere, it would mean that the left sphere is negatively charged since opposite charges attract. If it swings away, the left sphere would also have a positive charge due to the repulsion of like charges.