When a glass rod is rubbed with a silk cloth, charges appear on both. A similar phenomenon is observed with many other pairs of bodies. Ecplain how this observation is consistent with the law of conservation of charge.

Explanation

According to law of conservation of charge, "charge can neither be created nor be destroyed but it can be transferred from one body to another body". Before rubbing the two bodies they both are neutral i.e., the total charge of the system is zero. When the glass rod is rubbed with a silk cloth, some electrons are transferred from glass rod to silk cloth. Hence glass rod attains positive charge and silk cloth attains same negative charge.
Again the total charge of the system is zero, i.e. the charge before rubbing is same as the charge after rubbing. This is consistent with the law of xonservation of charge. Here we can also say that charges can be created only in equal and unlike pairs.