Question

Repulsion is a sure test of whether a body is charged or not.Justify the statement

Answer 1

we say that repulsion is a sure test of charge in body because we can test charge by only two way one is attraction and second is repulsion. as we know that an charged body attracts non charged body also. for ex. magnet attracts an non magnetic iron but an charged body can give repulsive force to only another charged body

Answer 2

We know that a charged object and an uncharged object attract each other. Also two charged objects having unlike charge attract each other. So if two objects attract each other, we cannot determine whether both are charged or only one is charged. Hence, attraction is not a foolproof way to treat for charge. However, if two object repel each other, we can be sure that both are charged (if they have the same charge). So, while testing for charge, repulsion is a foolproof way to test whether it's charge or not.

Hope it'll help.. :-D