(a) Silk cloth and Rubber balloon acquire negative charge. When a glass rod is rubbed with silk, some of the electrons from the glass atoms are transferred to silk. Due to the deficiency of electrons in the glass atoms, it becomes positively charged. Whereas the silk has acquired electrons, it becomes negatively charged. An inflated rubber balloon can be charged by rubbing it against the woolen cloth. Upon rubbing, the wool loses electrons and it causes the electrons to move from the wool to the balloon’s surface. The rubbed part of the balloon now has a negative charge.

(b) Glass rod and Woolen cloth acquire positive charge. When a glass rod is rubbed with silk, some of the electrons from the glass atoms are transferred to silk. Due to the deficiency of electrons in the glass atoms, it becomes positively charged. An inflated rubber balloon can be charged by rubbing it against the woolen cloth. Upon rubbing, the wool loses electrons and it causes the electrons to move from the wool to the balloon’s surface. The woolen cloth is left with a positive charge.