1.Why static electricity is called frictional electricity?

2.Explain "Repulsion is a surer test of electrification"

3.Explain "Attraction is not a surer test of electrification"

Dear student,

1. Static electricity is produced by rubbing to two objects. It is the friction between the two objects that generates attraction between the objects leading to charge transfer. It is due to this contribution of friction that static energy is also called frictional electricity.

2. and 3. Kindly refer to the following link:
https://www.meritnation.com/ask-answer/question/explain-why-repulsion-is-the-surer-test-for-electrification/electric-charges-and-fields/2295179

Please post again in case of further queries.
Regards.