A charged iron rod is brought near a metal ball that is mounted on an insulating pad. If the iron rod acquired negative charge, what must be the charge of the metal ball after charging?
To determine the charge of the metal ball after charging, we need to consider the process of charging by induction.
Charging by induction occurs when a charged object is brought near a conductor (in this case, the metal ball). The presence of the charged object causes a separation of charges within the conductor.
Since the charged iron rod is brought close to the metal ball, the negative charges in the iron rod will repel the electrons present in the metal ball, forcing them to move away from the region closest to the rod.
As a result, the side of the metal ball facing the charged iron rod will become positively charged while the opposite side (facing away from the rod) will become negatively charged as electrons accumulate there.
Therefore, the metal ball will acquire a positive charge on the side closest to the charged iron rod and a negative charge on the opposite side.
In this scenario, since the iron rod acquired a negative charge, the metal ball will acquire a positive charge after charging.