Question

Does the charging by friction violates law of conservation of charge?

Answer 1

The frictional charging process involves a transfer of electrons between two objects. Charge is not created from nothing. The appearance of negative charge upon a rubber balloon is merely the result of its acquisition of electrons. And these electrons must come from somewhere; in this case, from the object it was rubbed against. Electrons are transferred in any charging process. In the case of charging by friction, they are transferred between the two objects being rubbed together. Prior to the charging, both objects are electrically neutral. The net charge of the system is 0 units. After the charging process, the more electron-loving object may acquire a charge of -12 units; the other object acquires a charge of +12 units. Overall, the system of two objects has a net charge of 0 units. Whenever a quantity like charge (or momentum or energy or matter) is observed to be the same prior to and after the completion of a given process, we say that the quantity is conserved. Charge is always conserved.
When all objects involved are considered prior to and after a given process, we notice that the total amount of charge amidst the objects is the same before the process starts as it is after the process ends. This is referred to as the law of conservation of charge.