Basic Qualification · B-006 Feedlines and antenna systems · B-006-001-006
A transmitter is delivering radio frequency (RF) energy into a coaxial cable with a characteristic impedance of 50 ohms. The cable is terminated by a purely resistive load. What value of load resistance will absorb all the RF energy it receives?
- A25 ohms
- B100 ohms
- C200 ohms
- D50 ohms
Correct answer: D — 50 ohms. From the official ISED question bank, verified word for word.
Why
When a coaxial cable has a characteristic impedance of 50 ohms, it absorbs all radio frequency energy only if the load resistance at the end also equals 50 ohms. 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