Electric circuit: The closed path along which electric current flows is called an electric circuit.
Conventional symbols used to represent some of the most commonly used electrical components are given:
Positive and negative charges: The charge acquired by a glass rod when rubbed with silk is called positive charge and the charge acquired by an Ebonite rod when rubbed with wool is called negative charge.
Static and current electricity: Static electricity deals with the electric charges at rest while the current electricity deals with the electric charges in motion.
Conductor: A substance which allows passage of electric charges through it easily is called a conductor. A conductor offers very low resistance to the flow of current. For example copper,silver, aluminium etc.
Insulator: A substance that has infinitely high resistance does not allow electric current to flow through it. It is called an insulator. For example rubber, glass, plastic, Ebonite etc.
Coulomb’s Law: The mutual electrostatic force between two point charges q₁ and q₂ is proportional to the product q₁ q₂ and inversely proportional to the square of the distance r₂₁ separating them.