The Law of Conservation of Charge states that the net electric charge of an isolated system never changes; charge is neither created nor destroyed, only transferred.
Quantization of Charge implies that any observable charge must be an integer multiple of the elementary charge, expressed as , where is an integer.
Electrostatic Forces govern the interaction between charges: like charges exert a repulsive force on each other, while opposite charges exert an attractive force.
The magnitude of the force between two point charges is proportional to the product of the charges and inversely proportional to the square of the distance between them.
| Feature | Conductors | Insulators |
|---|---|---|
| Electron Mobility | Electrons move freely through the lattice | Electrons are tightly bound to atoms |
| Charge Distribution | Charge resides on the outer surface | Charge remains localized where it was placed |
| Examples | Metals (Copper, Gold), Graphite | Plastics, Glass, Rubber |
Static Electricity refers to the buildup of electric charge on the surface of an object, typically an insulator, where the charge cannot flow easily.
Current Electricity involves the continuous flow of electric charge through a conductor, driven by a potential difference.
Identify the Carrier: Always remember that in solid materials, only electrons move. If an object becomes positive, explain it as a 'loss of electrons' rather than a 'gain of protons'.
Field Line Direction: When drawing electric fields, lines must always point away from positive charges and towards negative charges.
Force Relationships: If the distance between two charges doubles, the electrostatic force between them decreases to one-fourth () of its original value.
Neutral Attraction: Remember that a charged object can attract a neutral object through induction, so attraction does not always prove both objects are charged.
Proton Movement: A common error is stating that protons move to create a positive charge. Protons are bound in the nucleus; only valence electrons are mobile.
Charge Creation: Students often think rubbing 'creates' charge. Rubbing only provides the energy to 'transfer' existing electrons from one material to another.
Neutrality vs. No Charge: 'Neutral' does not mean an object has no charge; it means the total positive charge exactly balances the total negative charge.
