What Happens to the Charge on a Grounded Sphere Near a Charged Rod?

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SUMMARY

When a negatively charged rod is brought near a grounded metal sphere, it induces a separation of charges within the sphere, resulting in negative charges accumulating on the far side and positive charges on the near side. Grounding the sphere allows these negative charges to escape, leaving the sphere positively charged once the rod and grounding finger are removed. The final charge on the sphere is positive due to the loss of electrons, confirming that grounding facilitates charge removal in response to external electric fields.

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A negatively charged rod is brought near a suspended metal sphere. The sphere is 'grounded' by touching it with a finger. The finger and the rod are now removed. What charge will be on the sphere, positive or negative? Explain what happens.

Initially I thought that the finger would remove any induced charge that the sphere took on from the rod, but now I'm questioning that position. Can someone explain to me whether I'm wrong, and if so, how things really work?

Thanks.
 
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When you bring the rod close to the sphere, you induce negative charges on the far side of the sphere and positive charges on the near side. Basically, the electrons on the sphere want to be as far away from the rod as possible. By grounding the sphere you provide a path for these electrons (negative charges) to leave the sphere and this is exactly what they wanted. So the negative charges leave the sphere, making it ...
 
I see. So if the rod and the finger were both on the same side and then removed, then the change in charge of the sphere would ideally be zero?
 

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