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2 neutral metal spheres, A and B, are touching each other.

A negatively charged rod is brought near to B.
(a) Draw the charges induced on the 2 spheres.

The negatively charged rod is now brought closer to touch B.
(b) Explain why A momentarily moves away from B.

i need help with b

2 neutral metal spheres, A and B, are touching each other. A negatively charged rod-example-1
User Lee Buckle
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1 Answer

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17 votes
Since the rod is brought near B, it becomes momentarily polarized, so the electrons in B move to A and it becomes net negative, and B is net positive. But since protons can’t move from sphere to sphere(only electrons) A also becomes polarized on its own, and all electrons are on the left and all protons on the right, since the protons are also attracted to the negative rod. Therefore, since unlike charges repel, A moves away from B.
User Zecuria
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