TEM mode exists in
- A. A circular wave guide
- B. A rectangular wave guide
- C. A co-axial cable
- D. None of the transmission lines
Answer: C. A co-axial cable
Explanation: Transverse Electromagnetic (TEM) mode requires at least two conductors to exist. Coaxial cables have two conductors (inner and outer), whereas standard rectangular or circular waveguides are single-conductor hollow structures and do not support TEM mode.