A positive electric charge

An object gains excess negative charge after being rubbed against another object,
which is:

Two uncharged objects A and B are rubbed against each other. When object B is placed near a negatively charged object C, the two objects repel each other. Which
of the following statements is true about object A?

When you rub a plastic rod against your hair several times and put it near some bits
of paper, the pieces of papers are attracted towards it. What does this observation
indicate?

According to Coulomb’s law, what happens to the attraction of two oppositely
charged objects as their distance of separation increases?

The Coulomb’s law is valid for the charges which are

A positive and a negative charge are initially 4 cm apart. When they are moved
closer together so that they are now only 1 cm apart, the force between them is

Five joules of work is needed to shift 10 C of charge from one place to another. The
potential difference between the places is

Two small charged spheres are separated by 2 mm. Which of the following would
produce the greatest attractive force?

Electric field lines

Capacitance is defined as