In a series circuit, how does current flow and how are voltages distributed?

• A. The current is different in each component; voltages add to the source.
• B. The same current flows through all components; total voltage is the sum of individual voltages.
• C. Each component has the same voltage; current equals the source.
• D. Current increases through the chain as more components are added.

Answer: (B)

In a series circuit, the same current flows through every component, and the voltages across the components add up to the source voltage. Since there’s only one path for charge, the current that leaves the source must pass through each component in turn, so it stays the same everywhere in the loop. The voltage across each component depends on its resistance (V = I × R), so different parts can drop different amounts of voltage, but if you add all those drops together, you recover the total voltage provided by the source. If you add more components in series, the total resistance goes up, which lowers the current according to I = V / R_total.

This is why the statement that the same current flows through all components and the total voltage is the sum of the individual voltages is the correct description. The idea that current changes from component to component, or that every component has the same voltage, or that current increases as you add more components, does not fit how series circuits behave.