NEIEP Mechanics Practice Exam

Which statement best describes the relationship between voltage and current in a series circuit?

1. Voltage is constant while current changes

2. Current is constant while voltage changes

3. Both voltage and current are constant

4. Voltage and current are unrelated

The correct answer is: Current is constant while voltage changes

In a series circuit, the current remains constant throughout all components connected in the circuit. This constancy is due to the nature of series circuits, where the same amount of current flows through each component without any branching. The voltage, however, is distributed among the various components according to their resistance. As individual resistors are added, the total voltage supplied by the power source is divided among those resistors, leading to changes in voltage across each component depending on their resistance values. This relationship is defined by Ohm's Law (V = IR), where the total voltage is the product of the current and the total resistance in the circuit. Therefore, while the voltage may vary across the different components, the current flowing through the entire circuit remains consistent. This fundamental principle is crucial for understanding how series circuits operate in electrical systems.