Basic Qualification · B-007 Radio wave propagation · B-007-002-007
When is ionization at a minimum in the ionosphere?
- AShortly before midnight
- BShortly before dawn
- CJust after noon
- DJust after dusk
Correct answer: B — Shortly before dawn. From the official ISED question bank, verified word for word.
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