Question

Explain why a charged comb attraction bits of paper?

Answer 1

The reason why the pieces of paper are neutral is that they contain equal amount of positive and negative charges and so they cancel each other out.
When you bring a charged plastic comb to the pieces of paper, the charge opposite to that of the plastic comb will be brought to a part of the surface of the paper where the plastic comb is. Opposite charges attract each other, and since you're holding the comb, the pieces of paper will be attracted to the comb.