Cathodic Protection Tester Practice Exam

According to Kirchhoff's laws, what relationship exists between total power voltages and voltage drops?

1. Total power voltages exceed voltage drops

2. Some power voltages equal the sum of voltage drops

3. Voltage drops are always greater

4. Power voltages are unrelated to voltage drops

The correct answer is: Some power voltages equal the sum of voltage drops

The correct answer reflects Kirchhoff's Voltage Law (KVL), which states that the sum of the electromotive forces (power voltages) in any closed circuit is equal to the sum of the potential drops (voltage drops) across all the components in that circuit. This principle arises from the conservation of energy, ensuring that the energy supplied by power sources is entirely accounted for by the energy consumed by the components within the circuit. In this context, the relationship established by KVL implies that when you measure the total voltage supplied by sources in a circuit, that amount will be equal to the total of the voltage drops that occur across resistive, capacitive, and inductive components within the same closed loop. Each voltage drop corresponds to a decrease in electrical potential energy as current flows through a component, while the power voltages represent the energy supplied to push the current through. Thus, the total power contributions from these sources balance out exactly with the energy dissipated across the circuit's resistive elements, corroborating the statement that some power voltages equal the sum of the voltage drops. Understanding this relationship is vital in the context of electrical circuits as it allows for the analysis of circuit behavior, ensuring that designers and engineers can predict how voltages will behave