Basic Qualification · B-007 Radio wave propagation · B-007-005-002
How long is an average sunspot cycle?
- A 7 years
- B 11 years
- C 17 years
- D 5 years
Correct answer: B — 11 years. From the official ISED question bank, verified word for word.
Why
The Sun goes through a regular pattern where the number of sunspots, which are dark, cooler areas on its surface, rises and falls over time. 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.