Electric Charge and Static Electricity Notes

Electric Charge

• All matter is made of atoms containing protons (+), neutrons (0), and electrons (-).

Law of Electric Charges

• Like charges repel; opposite charges attract.
• Protons (+) and electrons (-) attract.

Electric Force

• The force between charged objects.
• Depends on:
  • Amount of charge: greater charge = greater force.
  • Distance: greater distance = less force.

Electric Field

• Region around a charged object where electric forces can be exerted.

Charged Objects

• Atoms are neutral when the number of protons and electrons are equal.
• Objects are charged by gaining or losing electrons.

Charging Methods

• Friction: Electrons are transferred by rubbing.
• Conduction: Electrons move through direct contact.
• Induction: Charges are rearranged without direct contact.
• Only electrons move.

Conservation of Charge

• Charges are neither created nor destroyed; they move from one atom to another.

Conductors and Insulators

• Conductor: Materials in which charges move easily (e.g., metals).
• Insulator: Materials in which charges cannot move easily (e.g., plastic, rubber).
• Semiconductors: Materials with conductivity between conductors and insulators (e.g., silicon).

Static Electricity

• Electric charge at rest on an object.

Electric Discharge

• The loss of static electricity as charges move off an object.

Lightning

• Rapid electric discharge due to charge differences, often during thunderstorms.
• Lightning rods provide a grounded path for electric charges to move to Earth, preventing damage to buildings.