Extra exam question E9F10
Subelement E9, ANTENNAS AND TRANSMISSION LINES· Group E9F
What impedance does a 1/8-wavelength transmission line present to an RF generator when the line is shorted at the far end?
- A.A capacitive reactance
- B.The same as the characteristic impedance of the line
- C.An inductive reactance (correct answer)
- D.Zero
WhyA 1/8-wavelength transmission line shorted at the far end presents an inductive reactance to an RF generator. A shorted 1/8-wavelength line is shorter than the 1/4-wavelength needed to fully invert a short circuit into an open, so it presents an inductive reactance at its input, an intermediate impedance between the pure short at the far end and the pure open a full quarter-wave shorted line would present, answer C. It doesn't present a capacitive reactance, doesn't simply repeat the line's characteristic impedance, and it isn't zero, that would only be true exactly at the shorted far end itself, not looking into 1/8 wavelength of line.
Published 2026-08-28 · Last updated 2026-08-28 · Question text is verbatim from the 2024-2028 NCVEC Element 4 pool (public domain); the explanation above is original writing, see our methodology.
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