Final answer:
Surface charge originates through multiple mechanisms such as the distribution of electrostatic charge on conductors, charging by contact or friction, polarization in dielectrics, and chemical reactions in batteries.
Step-by-step explanation:
The main mechanisms for origin of surface charge include the electrostatic distribution on conductors, charging by contact or friction, separation of charge in atoms and molecules, and chemical reactions such as those occurring in batteries. When a charge is placed on a spherical conductor, the like charges repel each other and spread out uniformly over the surface. However, if the conductor has an irregular shape, the charge tends to concentrate at sharp points or edges.
In addition to conductors, non-conductive materials, or dielectrics, can also exhibit surface charges due to polarization. When these materials are placed in an electric field, the atomic and molecular charges can shift slightly, causing one side of the molecule to be more positive and the other more negative, resulting in induced surface charges.
Charging can also occur through friction, as when materials are rubbed together. The material with a greater affinity for electrons becomes negatively charged, and the other positively charged. Likewise, chemical interactions in batteries facilitate the transfer of electrons, causing one terminal to become negative and the other positive, leading to a separation of charge at the macroscopic level.