Positive charge
Explanation
The phenomenon of acquiring electric charge through friction is known as frictional electricity or the triboelectric effect. When two different materials are rubbed together, electrons are transferred from one material to the other based on their electron affinity (work function). The historical convention for naming these charges was established by Benjamin Franklin.
Detailed Analysis
- Mechanism of Charge Transfer: When a glass rod is rubbed with silk, loosely bound electrons from the atoms of the glass rod are transferred to the silk cloth.
- Resulting Charge: Since electrons carry a negative charge, the loss of electrons results in a deficit of negative charge on the glass rod. Consequently, the glass rod acquires a net positive charge.
- Conservation of Charge: The silk cloth, having gained the electrons lost by the glass, acquires an equal magnitude of negative charge. The total charge of the isolated system remains conserved.
Key Takeaway: By convention, a glass rod rubbed with silk acquires a positive charge, whereas a plastic or ebonite rod rubbed with fur or wool acquires a negative charge.