Plastic straws A and B are rubbed with a dry cotton cloth. What will happen, if the straws are brought near each other?

Plastic straws A and B are rubbed with a dry cotton cloth. If the straws are brought near each other, they acquire the same charge and hence repel each other.

When two dissimilar materials are rubbed together, electrons from one substance are transferred to the other. As a result, when an object loses an electron, it becomes positively charged, whereas when an object gains an electron, it becomes negatively charged. 

A positively charged object will draw a negatively charged object, according to our fundamental theory of charge interaction. In contrast to the attractive force that exists between two items with opposing charges, two objects with the same charge repel one another.

The plastic straws and cotton fabric receive equal and opposite charge when they are rubbed together. And as the same charges repel, when plastic straws A and B are rubbed with a dry cotton cloth, and brought close to one another, they will repel one another.