Which description defines a series circuit?

• A. Three-phase power system
• B. Circuit with multiple paths
• C. Fuse
• D. Circuit with one path

Answer: (D)

The main idea being tested is how components are arranged in a circuit and how that affects current flow. In a series circuit, there is only one continuous path for current to travel from the source, through each component in sequence, and back to the source. That single path is what the option describes as a circuit with one path. Because there’s just one path, the same current flows through every component, and the total resistance is found by adding the individual resistances together. If any part of the circuit opens or fails, the path is broken and the entire circuit stops conducting.

The other descriptions don’t match a series arrangement. A three-phase power system involves multiple phases and conductors, not a single path through all components. A circuit with multiple paths describes a parallel circuit, where current can split. A fuse is a protective device used to interrupt current during faults, not a description of how the circuit’s paths are arranged.