Advanced Qualification · A-007 Feedlines and matching · A-007-004-008
The impedance of a half-wave antenna at its centre is low, because at this point:
- A voltage is low and current is high
- B voltage and current are both high
- C voltage and current are both low
- D voltage is high and current is low
Correct answer: A — voltage is low and current is high. From the official ISED question bank, verified word for word.
Why
At the exact centre of a half-wave antenna, the electrical pressure, or voltage, drops to its lowest point while the flow of electricity, known as current, reaches its peak. The full explanation — and one for every question — is in Pro.
Practise this section
Feedlines and matching at the advanced level: transmission line theory, impedance transformation, stubs and matching networks.