Basic Qualification · B-006 Feedlines and antenna systems · B-006-008-003
What is the wavelength in free space of a 25 MHz signal?
- A19 metres
- B39 metres
- C6 metres
- D12 metres
Correct answer: D — 12 metres. From the official ISED question bank, verified word for word.
Why
A 25 MHz signal has a wavelength of 12 metres because radio waves travel at the speed of light, which is roughly 300 million metres per second. The full explanation — and one for every question — is in Pro.
Practise this section
Feedlines and antenna systems is section B-006 of the Basic exam: Getting the signal out: antennas, feedlines, SWR, baluns, matching, and why antenna length depends on frequency.
Drill B-006 — free, no account