Basic Qualification · B-007 Radio wave propagation · B-007-005-009
La durée moyenne d'un cycle solaire est de:
- A1 an
- B11 ans
- C3 ans
- D6 ans
Correct answer: B — 11 ans. Question tirée de la banque officielle d'ISDE.
Why
The Sun follows a natural rhythm where its magnetic activity, including sunspots and solar flares, rises and falls over a period of roughly 11 years. The full explanation — and one for every question — is in Pro.
Practise this section
Radio wave propagation is section B-007 of the Basic exam: How signals travel: the ionosphere and its layers, skip, ground wave, sporadic E, and which bands work when.
Drill B-007 — free, no account