In which circuit does current travel through a single path through all components, resulting in total resistance equal to the sum of the individual resistances?

• A. Parallel circuit
• B. Open circuit
• C. Series circuit
• D. Open/Closed circuit

Answer: (C)

In a series circuit, current travels along a single path through every component. Because the same current passes through each element, the voltage drops across them add up, and the total opposition to the current—the total resistance—is simply the sum of the individual resistances. This is why the total resistance is R1 + R2 + ...; each component adds its own resistance to the same current, so they stack together in series.

If it were a parallel arrangement, the current would split among different paths, not stay on one path, so the total resistance would not be the sum. An open circuit has a break in the path, so no current flows and you don’t get a simple sum of resistances. The term open/closed circuit isn’t a standard descriptor for this behavior.