Three objects are brought close to each other, two at a time. When objects A and B are brought together, they attract. When objects B and C are brought together, they repel. From this, we conclude that:
(a) objects A and C possess charges of the same sign.
(b) objects A and C possess charges of opposite sign.
(c) all three of the objects possess charges of the same sign.
(d) one of the objects is neutral.
(e) we need to perform additional experiments to determine information about the charges on the objects.
From this question, I thought we can create two scenarios:
A and B attract, so I thought they have to be opposite signs. B and C repel, so they must be the same sign. I was surprised when I saw solutions, the selected answer was just (e).
Answer: (e). In the first experiment, objects A and B may have charges with opposite signs, or one of the objects may be neutral. The second experiment shows that B and C have charges with the same signs, so that B must be charged. But we still do not know if A is charged or neutral.
I thought a neutral charged object would have no affect. Since when does a neutral charge and charged object attract? Is this implying that two objects with a neutral charge and an object that is positive or negative will attract? And is this attractive referring to induction?