How can you represent experimentally that $(i)$ there are two types of charges and $(ii)$ there is repulsion between two like charges and attraction between two unlike charges ?

Only two types of charges are there on different bodies that is proved by following two experiments.

- Experiment $1$

If two glass rods rubbed with wool or silk cloth are brought close to each other, they repel each other as shown in figure $(a)$.

The two strands of wool or two pieces of silk cloth, with which the rods were rubbed, also repel each other.

However, the glass rod and wool attracted each other as shown in figure (b) but attracted the fur.

On the other hand, the plastic rod attracts the glass rod as shown in figure (c) and repel the silk or wool with which the glass rod is rubbed.

If a plastic rod rubbed with fur is made to touch two small pith balls (polystyrene balls) suspended by silk or nylon thread, then the balls repel each other as shown in figure (d) and are also repelled by the rod.

* Experiment $2$

A similar effect is found if the pith balls are touched with a glass rod rubbed with silk as shown in figure $(e)$.

A dramatic observation is that a pith ball touched with glass rod attracts another pith ball touched with plastic rod as shown in figure $(f).$

It is concluded after many careful studies by different scientists, that there were only two kinds of an entity which is called the electric charge.

There are two types of charges: Positive and negative like charges repel and unlike charges attract each other.

The experiments also demonstrated that the charges are transferred from the rods to the pith balls on contact. It is said that the pith balls are charged by contact.

The property which differentiates the two kinds of charges is called the polarity of charge.