General exam question G3C02
Subelement G3, RADIO WAVE PROPAGATION· Group G3C
What is meant by the term “critical frequency” at a given incidence angle?
- A.The highest frequency which is refracted back to Earth (correct answer)
- B.The lowest frequency which is refracted back to Earth
- C.The frequency at which the signal-to-noise ratio approaches unity
- D.The frequency at which the signal-to-noise ratio is 6 dB
WhyThe critical frequency at a given incidence angle is the highest frequency that is refracted back to Earth at that angle. The critical frequency at a given incidence angle is the highest frequency that still gets refracted back to Earth at that angle rather than passing straight through into space, answer A. It isn't the lowest such frequency, and it isn't defined by any particular signal-to-noise threshold, those describe different concepts entirely.
Published 2026-08-28 · Last updated 2026-08-28 · Question text is verbatim from the 2023-2027 NCVEC Element 3 pool (public domain); the explanation above is original writing, see our methodology.
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