IMathAS-libretexts

Spheres A and B are identical in size and made from the same conducting material. Sphere A is attached to an insulating rod, and sphere B is suspended from an insulating thread. Sphere A initially has a charge of +10â€‰nC, and sphere B is initially uncharged.

Spheres A and B are put briefly into contact. Which of the following best explains the resulting charge on spheres A and B?

A charge that is equal in magnitude and sign to the charge on sphere A will be attracted onto sphere B, so both spheres will have a charge of +10â€‰nC.
A charge that is equal in magnitude and opposite in sign to the charge on sphere A will be attracted onto sphere B, so sphere A will still have a charge of +10â€‰nC and sphere B will have a charge of âˆ’10â€‰nC.
The net charge on identical conductors is shared equally when they are put into contact, so both spheres will have a charge of +5â€‰nC.
Before sphere A and sphere B are brought into contact, sphere A will polarize sphere B , resulting in a net charge of âˆ’5â€‰nC on the near side of sphere B and +5â€‰nC on the far side of sphere B . When sphere A and sphere B are in contact, the charge âˆ’5â€‰nC on the near side of sphere B will move onto sphere A , resulting in sphere A having a net charge of +5â€‰nC and sphere B having a net charge of âˆ’5â€‰nC .

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