Mechanism of Charging of an Object

Electric charging is the process by which a neutral object acquires a net positive or negative charge due to the transfer or redistribution of electrons between bodies. The nucleus (protons and neutrons) remains fixed, while electrons — being loosely bound in outer orbits — are free to move between materials.

• Atoms are electrically neutral in their normal state (equal protons and electrons).
• Rubbing, contact, or proximity between two different materials disturbs this balance.
• Electrons move from the material with weaker electron-holding capacity to the one with stronger capacity.
• The material losing electrons becomes positively charged; the material gaining electrons becomes negatively charged.

Key Condition: Electron transfer during rubbing occurs only when the two bodies are made of different materials.

Process of creating an imbalance between protons and electrons in a body, giving it a net electric charge.

Charging that occurs when two different materials are rubbed together, causing electron transfer.

Charging by direct physical contact between a charged and an uncharged conductor.

Charging without direct contact, caused by the redistribution of charge due to a nearby charged body.

A ranked list of materials based on their tendency to gain or lose electrons on contact.

1. Charging by Friction: Two dissimilar materials are rubbed together; electrons transfer from one to the other.
   Example: Rubbing a glass rod with silk cloth — glass loses electrons (becomes positive), silk gains electrons (becomes negative).
2. Charging by Conduction: A charged conductor is brought into direct contact with a neutral conductor, allowing charge to flow until equilibrium is reached.
3. Charging by Induction: A charged body is brought near (not touching) a neutral conductor, causing internal charge redistribution — the near side gets an opposite charge, the far side gets a similar charge.

Since an electron has a (very small but nonzero) mass:

The triboelectric series ranks materials by their tendency to lose or gain electrons when rubbed. Materials earlier in the list tend to lose electrons (become positive); materials later in the list tend to gain electrons (become negative).

When you rub a plastic comb on dry hair, the comb pulls electrons from the hair. The comb becomes negatively charged and can then attract small bits of paper — the same principle explains why a balloon sticks to a wall after rubbing it on wool.

• Charging results from electron transfer, not proton movement.
• Three methods: Friction, Conduction, Induction.
• Charge follows the Law of Conservation of Charge — total charge in an isolated system remains constant.
• Triboelectric series predicts polarity of charge when two materials are rubbed.
• Losing electrons → positive charge, slight mass decrease.
• Gaining electrons → negative charge, slight mass increase.