Extra exam question E3C02
Subelement E3, RADIO WAVE PROPAGATION· Group E3C
What is indicated by a rising A-index or K-index?
- A.Increasing disturbance of the geomagnetic field (correct answer)
- B.Decreasing disturbance of the geomagnetic field
- C.Higher levels of solar UV radiation
- D.An increase in the critical frequency
WhyA rising A-index or K-index indicates increasing disturbance of Earth's geomagnetic field. A rising A-index or K-index indicates increasing disturbance of Earth's geomagnetic field, the standard measures used to track how stirred up the magnetosphere is at any given time, answer A. A rising index doesn't indicate decreasing disturbance, doesn't measure solar UV levels directly, and doesn't indicate a rising critical frequency, that's a separate ionospheric measurement.
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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