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. Explain, how this observation is consistent with the law of conservation of charge?

Explanation

When a glass rod is rubbed with a silk cloth, charges appear on both, these charges are equal in magnitude and opposite in sign, so that algebraic sum of the charges produced on both is zero. The net charge on the two bodies was zero even before rubbing them. Thus, we find that charges can be created only in equal and unlike pairs. This is consistent with the law of conservation of charge.