According to Electronic Theory of Electric Charging "A body can be charged by the transfer of electrons".
- The process of developing charge in a body is called electrification.
- Matter is made up of atoms, Each atom has positive as well as negative charges.
- Positive charge (protons) is present in the nucleus of the atoms and negative charge (Electrons) revolves around the nucleus.
- In an atom, the number of positivity charged (protons) must be equal to the number of negatively charged electrons.
- Hence , the net charge on an atoms is zero. Therefore , matter is electrically neutral.
- The atoms of different substances hold the electrons in their outermost orbits with different strength.
- The maximum energy required to remove an electron from an atom is called work function.
- Smaller the work function easier will be the removal of electron and vice-versa.
- Metals have a low value of work function and that for non-metal is high.
- When two Bodies are rubbed together , electrons in the outermost orbits of atoms of a body get transferred to the other body according to their affinity (ability of gaining electrons ).
- Affinity of ebonite for electrons is more than that of fur. When ebonite is rubbed with fur, outermost electrons of the atoms of fur go to ebonite .
- Thus ebonite with more electrons gets some net negative charge whereas fur having less electrons gets some net positive charge.
- A charge associated with a proton is known as positive charge. The charge on proton = +1.6 × 10-19 C.
- A charge associated with a electron is known as negative charge. The charge on an electron = -1.6× 10-19C
- The material which lose electrons are said to have positive charge, it's mass decrease.
- The material which gaining electrons are said to have negative charge, it's mass increase.
- The mass of a positively charged body is less than the mass a neutral body.
- Decrease in the mass of a positively charged body = number of electrons lost by body × mass of an electron.
- The mass of a negativity charged body is more than the mass a neutral body.
- Increase in the mass of a negativity charged body = number of electrons gained by body × mass of an electron.
- Mass of one electron is 9.1 × 10-31 kg and mass of one proton is 1.67 × 10-27 kg so proton is heavy than electron so Protons are not responsible for the transfer of charges on rubbing
- Protons and neutrons in the nucleus are bound by nuclear force which are much stronger than the force between electrons and nucleus.