How can you determine the voltage drop across a resistor in a circuit?

The formula for calculating the voltage drop across a resistor is derived from Ohm's Law, which states that voltage (V) is equal to the current (I) flowing through the resistor multiplied by the resistance (R) of that resistor. This relationship is represented by the equation V = IR.

In this context, the voltage drop across the resistor indicates how much electrical energy is converted into heat or used in the circuit as the current flows through the resistor. The greater the current or resistance, the higher the voltage drop. This principle is fundamental in both AC and DC circuits and is essential for designing and analyzing electronic systems.

Other choices provide incorrect formulations that do not represent how voltage, current, and resistance interact according to Ohm's Law. For example, dividing power by resistance does not yield voltage in the dimensional sense, and adding current to resistance does not reflect any direct physical relationship relevant to electrical circuits.