General exam question G3A11
Subelement G3, RADIO WAVE PROPAGATION· Group G3A
How long does it take a coronal mass ejection to affect radio propagation on Earth?
- A.28 days
- B.14 days
- C.4 to 8 minutes
- D.15 hours to several days (correct answer)
WhyA coronal mass ejection typically takes 15 hours to several days to reach Earth and affect radio propagation. A coronal mass ejection is a much slower-moving cloud of charged particles than a flare's burst of light, so it typically takes anywhere from about 15 hours to several days to reach Earth and disturb propagation, answer D. The 28-day and 14-day figures describe unrelated solar cycles, and the 4-to-8-minute range describes light-speed effects like flares, not the much slower CME plasma.
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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