Basic Qualification · B-007 Radio wave propagation · B-007-002-006
When is the ionosphere most ionized?
- A Midnight
- B Dusk
- C Midday
- D Dawn
Correct answer: C — Midday. From the official ISED question bank, verified word for word.
Why
The ionosphere is most ionized at Midday because the Sun's ultraviolet radiation is strongest when it is directly overhead, stripping electrons from atoms in the upper atmosphere. The full explanation — and one for every question — is in Pro.
Practise this section
How signals travel: the ionosphere and its layers, skip, ground wave, sporadic E, and which bands work when.