Five balls numbered $$1$$ to $$5$$ are suspended using separate threads. Pairs $$(1,2), (2,4), (4,1)$$ show electrostatic attraction while pairs $$(2,3), (4,5)$$ show repulsion. There ball $$1$$ must be
The correct options are
D made of metal
Ball 2 is positively charged then ball 4 s negatively charged because 2 and 4 show attraction. Now, if ball 2 is positively charged then ball 3 is also positively charged because 2 and 3 show repulsion and similarly, ball 5 is negatively charged since 4 and 5 show repulsion. And now, we are left with ball 1 and it can never be positively charged because ball 2 and 1 show attraction, it means ball 1 s negatively charged but it is also not possible because ball 1 and 4 also show attraction. So, ball 1 is neither positively nor negatively charged. It means ball 1 is neutral and made of metal.