Sure check for presence of electric charge is
Process of induction
Repulsion between bodies
Attraction between bodies
Frictional force between bodies
Find change in mass of a body if it is given $+2C$ charge.
What are positive and negative charges ? Which type of charge does electron have ?
What are called conductors and non-conductors ? In which free electrons are more ? Conductor or non-conductor.
Discuss the method of charging of two spheres by without contact method.