Question

prove by experiment that repulsion is the surest test of electrification

Answer 1

Attraction may occur between two oppositely charged bodies or a charged body and an uncharged one. That is why in attraction, one is not sure if both bodies are charged, However in repulsion, there are two bodies that have the same charge. That is why repulsion is the sure test of electrification.
Attraction can takes place b/w neutral bodies due to induction. But two bodies will repel only if they have opposite charge so we take repulsion as sure test of electrification.
Repulsion is sure to test of charge of a body because of it indicates that the other object is charged and has charge opposite to that of first object.
Hope it helps! ^^

Answer 2

Attraction may occur between two oppositely charged bodies or a charged body and an uncharged one. That is why in attraction, one is not sure if both bodies are charged, However in repulsion, there are two bodies that have the same charge. That is why repulsion is the sure test of electrification.

Attraction can takes place b/w neutral bodies due to induction. But two bodies will repel only if they have opposite charge so we take repulsion as sure test of electrification.

Repulsion is sure to test of charge of a body because of it indicates that the other object is charged and has charge opposite to that of first object.