Basic Qualification · B-007 Radio wave propagation · B-007-002-001
What causes the ionosphere to form?
- A Solar radiation ionizing the outer atmosphere
- B Lightning ionizing the outer atmosphere
- C Release of fluorocarbons into the atmosphere
- D Temperature changes ionizing the atmosphere
Correct answer: A — Solar radiation ionizing the outer atmosphere. From the official ISED question bank, verified word for word.
Why
The ionosphere forms when high-energy solar radiation strikes the outer atmosphere, knocking electrons loose from gas atoms to create charged particles called ions. 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.