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Take the following diagram and explanation:

enter image description here

I have two questions:

  1. Why is the table tennis ball with metal paint attracted to the positively charged rod. Although the negative charges move closer to the positively charged rod, isn't the ball still electrically neutral. So why is it still attracted? Is it because the negative charges are now closer to the rod, so that attraction is now greater than the repulsion between like charges, or something along those lines.

  2. If the two objects were close together, and for a brief moment, a grounding wire touched the ball, what would happen? In the answers it says the negative charges would flow up the earth wire. But why is this the case? Shouldn't electrons instead flow down to Earth.

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  • $\begingroup$ Yes, your answer is correct for the first question but for the second one you are wrong. Electrons will not flow to the earth since they are already bound to the positive charge of the rod. So, it will be the electrons from the earth that will come and neutralize the positive half of the ball making it negative finally. $\endgroup$ Jul 8 at 13:02

1 Answer 1

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The left-hand diagram shows that the ball is charged by induction with the net charge on it still zero.

Is it because the negative charges are now closer to the rod, so that attraction is now greater than the repulsion between like charges, or something along those lines. Yes

enter image description here

In the right-hand diagram think of it as the positive charges trying to get as far from one another as possible which is equivalent to electrons coming up from the ground.

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