Which term refers to a transmission line consisting of two conductors that are concentric and insulated from each other?

• A. Commuter
• B. Circuit
• C. Coaxial cable
• D. Circular Mil

Answer: (C)

Two conductors that are concentric and insulated from each other describe coaxial cable. It has a central conductor, a surrounding dielectric insulator, and an outer concentric conductor (shield) that encloses the inner conductor. This geometry keeps the electric field within the dielectric and provides strong shielding from external interference, giving a predictable characteristic impedance and good performance at high frequencies. The outer conductor is often tied to ground to provide a return path and further reduce noise. This makes coaxial cable the right term for this type of transmission line. Other options don’t capture this concentric, insulated-conductor arrangement.