Applicable for A-Level, IB, DSE, AP-Level Exams
In electricity, there are three fundamental principals you need to grasp: current, voltage and resistance. Ohm's Law states that as long as resistance is kept constant, current and voltage is proportional. The fundamental definitions of V, I and R is crucial to learn in order to grasp the rest of the electricity chapter.
I-V Graphs is all about showing the relationship between potential difference and current. If a conductor obeys Ohm's Law, current is proportional to voltage and the graph will be a straight line through the origin. Non-ohmic conductors like the filament lamp has its curve flatten out due to electrical energy turning into heat energy and causing the metal to heat up - more vibrations cause electrons to move through the component more difficultly.
Resistance is voltage per unit current. Resistivity is porportional to resistivity. Resistivity is a measure of how much a particular material resists current flow.
Power is defined as the amount of enegry per unit time.
EMF is the amount of amount electrical energy converted to electrical energy per coulomb of charge. Internal resistance is the amount of volts lost per unit current.