How is voltage drop calculated in a circuit?

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

In this context, choice B is a specific instance of Ohm's Law applied to a particular resistor in the circuit, where V1 represents the voltage drop across that resistor, I1 is the current passing through it, and R1 is the value of that resistance. Thus, this formula directly provides the means to calculate the voltage drop across individual components when current flows through them.

Utilizing this relationship is crucial in circuit analysis as it helps determine how much voltage is consumed by components such as resistors, which can significantly impact the functioning of the circuit as a whole. Therefore, applying the correct formula allows for precise calculations necessary for effective circuit design and troubleshooting.