In the figure above, the initially uncharged insulating rod on the left is free
ID: 1609223 • Letter: I
Question
In the figure above, the initially uncharged insulating rod on the left is free to rotate on an insulating stand. End X is then rubbed with a piece of fur. End Z of a second insulating rod is also rubbed with fur and then brought near the first rod. As the second rod is moved around, it is that end Y of the first rod is attracted to end Z, and end X is repelled. Which of the following correctly describes the signs of the charges on ends X and Y, if any? Opposite Z' s charge Same as Z' s charge Opposite Z' s charge No net charge Same as Z' s charge Opposite Z' s charge Same as Z' s charge No net chargeExplanation / Answer
When you rub the X end of insulating rod with the fur, electrons are stripped away from the atoms in the end and transferred to the silk cloth. This leaves the glass rod with more positive than negative charge, so you get a net positive charge. Same goes for end Z of the second rod.
So end X of rod 1 and end Z of rod 2 is positively charged while end Y of rod 1 has no net charge because its electrons are still present.
Hence X and Z will repel with Z and Y will attract.
Hence answer is D