Basic Qualification · B-007 Radio wave propagation · B-007-002-007
Quand l'ionisation de l'ionosphère est-elle au minimum?
- AUn peu avant l'aurore
- BTout de suite après le milieu du jour
- CJuste après le crépuscule
- DUn peu avant minuit
Correct answer: A — Un peu avant l'aurore. Question tirée de la banque officielle d'ISDE.
Why
The ionosphere needs sunlight to keep its atoms ionized, so as night stretches on without the sun, the ionization slowly fades away. 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