Potential difference and power — common mistakes

Always choose the power formula ($P=VI$, $P=I^2R$, or $P=V^2/R$) that uses the known quantities in your problem. This simplifies calculations and reduces the chance of errors by avoiding intermediate steps.

Potential difference (V) provides the energy 'push' per unit charge, while power (P) is the rate at which this energy is delivered or consumed. They are directly related by the formula $P = VI$, meaning higher voltage or current, or both, result in greater power.

The different formulas ($P=VI$, $P=I^2R$, $P=V^2/R$) are derived using Ohm's Law ($V=IR$). They exist to allow you to calculate power using whichever two quantities (voltage, current, or resistance) you already know, making problem-solving more efficient and direct.

Potential difference (voltage) is the energy transferred per unit charge, acting as the 'driving force' that makes charges move. Current, on the other hand, is the rate of flow of charge itself – how many charges pass a specific point in the circuit per second. Voltage pushes the charges, and current measures their flow.