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?

(N/A) The existence of two types of charges on different bodies is demonstrated by the following experiments:
- Experiment $1$: When two glass rods,rubbed with silk or wool,are brought close to each other,they repel each other,as shown in figure $(a)$. Similarly,two plastic rods rubbed with fur also repel each other.
- Experiment $2$: When a glass rod rubbed with silk is brought near a plastic rod rubbed with fur,they attract each other,as shown in figure $(c)$.
- Pith Ball Experiment: If a pith ball is touched with a charged glass rod,it acquires a positive charge. If another pith ball is touched with a charged plastic rod,it acquires a negative charge. It is observed that two pith balls charged by the same type of rod repel each other (like charges),while a pith ball charged by a glass rod attracts a pith ball charged by a plastic rod (unlike charges).
Conclusion: These experiments confirm that there are only two types of electric charges,conventionally named positive and negative. Like charges repel each other,and unlike charges attract each other. The property that differentiates these two types of charges is called the polarity of charge.