Which term is a transmission line consisting of two conductors concentric with and insulated from each other?

• A. Commuter
• B. Circuit
• C. Coaxial cable
• D. Conductance

Answer: (C)

Two conductors concentric with and insulated from each other describe a coaxial cable. The inner conductor sits at the center, while an outer conductor surrounds it, with dielectric material between them. This arrangement confines the electric field mainly to the space between the conductors, giving a well-defined impedance and strong shielding from external noise. The outer conductor also provides the return path for signals, completing the transmission line. Other terms don’t fit this structure: a circuit is just any closed path for current, conductance is a material property, and a nonspecific term isn’t used to describe this two-conductor coaxial arrangement.