Suppos that you have a rod that is positively charged, a rod that is negatively charged and a stand that allows rotation. if you are handed a rod of unknown charge-state, could you determine if it has a positive charge, a negative charge or if it is neutral? explain

Question

anonymous · Answer

what if the unknown rod is an uncharged conductor? Wouldn't it just repel if you brought the negative rod close to it or the positive rod close to it

kainui · Answer

Depends on if it's labelled or not on the stand. Since like charges repel, you can know that your unknown charge rod is the same charge as the one on the stand it repels and of opposite sign of the one it attracts. Whether or not they're negative or positive can't be discerned unless the stand is labelled though.

If it was an uncharged conductor, nothing would happen. There's no charge, then no force to move anything. Perhaps you know the equation: $$F _{e}=k _{e}(q _{1}q _{2})/r^2$$

Force is dependent upon there being two charges. So if you plug in 0 for q1 or q2, your force will turn out to be 0 as well.