In the given picture the Ring A at the bottom is positively charged. Another Ring B is brought and placed over it. Ring B hovers at a certain height above A. What could be the charge on Ring B?
Positive
If the rings weren't charged , Ring A would fall right?
But being charged is sort of repelling them away.
so what kind of charges repel? Similar charges.
If ring A is positively charged, B must be positively charged!!
Can it be neutral??
Nope.
Because it is a metal, ring A would attract the negative charge on the bottom side of ring B. Instead of repelling they would attract even more!
Correct answer is 'Positive'