1. Friction method of charging: If we rubbed one body on other body electrons are transfered from one body to the other. Transfer of electrons takes place from lower work function body to body of heigher work function.
Glass + Silk—– Glass(+) + Silk(-)
Ebonite rod + Cat far—– Ebonite rod(-) + Cat far(+)
in glass are loosely bound in it than the electrons in silk. So, when glass and silk are rubbed together, the comparatively loosely bound electrons from glass get transferred to silk. As a result, glass becomes positively charged and silk becomes negatively charged. Electrons in fur are loosely bound in it than the electrons in ebonite. So, when ebonite and fur are rubbed together, the comparatively loosely bound electrons from fur get transferred to ebonite. As a result, ebonite becomes negatively charged and fur becomes positively.
The process of transfer of charge by contact of two bodies is known as conduction. If a charged body is put in contact with uncharged body, the uncharged body becomes charged due to transfer of electrons from one body to the other.
3. Electrostatic induction
If a charged body is brought near a neutral body, the charged body will attract opposite charge and repel similar charge present in the neutral body. As a result of this one side of the neutral body becomes negative while the other positive, this process is called ‘electrostatic induction’.