The electrification is a process by which a body gains or loses electrical charges.
They are those with excess or lack of electrons, so that:
a body is positively electrified \(\implies\) number of electrons \(\lt\) number of protons
a body is negatively electrified \(\implies\) number of electrons \(\gt\) number of protons
a neutral body \(\implies\) number of electrons \(=\) number of protons.
Conductors and Insulators
Conductors are materials that easily conduct electric current. Insulators are materials that offer extreme resistance to the electrical current.
Types of Electrification
Whenever we rub two initially neutral bodies, they get electrified with charges of opposite sign. The material, which has weakly bound electrons will give them to the other body, leaving a net positive charge. In contrast, the other body will be left with a net negative charge.
(+) \( \leftarrow \) rabbit skin \ glass \ mica \ wool \ cat fur \ silk \ cotton \ wooden \ amber \ ebonite \ copper \ sulfur \ celluloid \( \rightarrow \) (-) Whenever one rubs two elements of the series above, the left-hand side elements will give electrons to the elements on the right side.
Electrification by Contact
Whenever an electrified conductor comes into contact with another neutral conductor, the latter is electrified with the same charge present in the former. When the two conductors have the same dimensions and the same shape, after contact, both share the same amount of electric charge.
Electrification by Induction
When a conductor is electrified by induction, the charging process changes the charges at the electrified body, those charges will have opposite sign to the ones in the inductor.