Electricity: Current, Resistance and Potential Difference

An electric current is a flow of electric charge, and in solid conductors like metal wires, it’s the movement of electrons.
The potential difference (also known as voltage), measured in volts (V), propels these charges and makes them move and flow as a current.
The resistance in a circuit will impact how much current flows for a given potential difference.
Ohm’s law links the relation between current, resistance and voltage. It states that the current through a conductor between two points is directly proportional to the voltage across the two points.
Resistance can be measured using the equation: Resistance (R) = potential difference (V) ÷ current (I) with the unit of resistance, the ohm (Ω).
The more resistance there is, the harder it is for the current to flow.
Resistance in a wire or component can depend on various factors: its material, its length, its cross-sectional area, and its temperature.
Conductors have low resistance and insulators have high resistance. This is due to the arrangement and the amount of free electrons in their structure.
Metals are considered excellent conductors as they have a vast number of free electrons that can move easily and establish an electric current.
Components in a series circuit share the same current. However, if components are in parallel, the current is split between the different branches.
The total potential difference of the power source is shared between components in a series circuit but is the same across each component in a parallel circuit.
A potential difference-current graph can be used to measure a component’s resistance. For ohmic conductors (at a constant temperature), the current is directly proportional to the potential difference, resulting in a linear graph.
Resistors and lamps show varying graph patterns due to the increase in temperature with increasing potential difference, affecting the resistance.