Forces and Energy - Electric Circuits and Conductivity

An electric circuit is a continuous loop that allows the flow of electrons. It typically consists of a power source (cell/battery), conductors (wires), and a load (bulb/motor).

Electricity is a form of energy resulting from the existence of charged particles. The flow of these particles is called current ($I$), measured in Amperes ($A$).

Conductors are materials that allow electricity to flow through them easily. Most metals, such as Copper ($Cu$) and Gold ($Au$), are excellent conductors due to free-moving electrons.

Insulators are materials that do not allow electricity to flow easily, such as rubber, glass, and plastic. These are used for safety to coat wires.

A circuit must be 'closed' (complete) for electricity to flow. An 'open' circuit has a gap (like an open switch) that stops the current.

Energy transformation: In a simple circuit with a bulb, chemical energy in the battery is converted into electrical energy, which is then transformed into light and heat energy ($Q$).

Resistance ($R$) is a measure of how much a material opposes the flow of electric current, measured in Ohms ($\Omega$).