Advanced Qualification · A-001 Advanced theory · A-001-003-011
What is the value of capacitance (C) in a series R-L-C circuit, if the circuit resonant frequency is 14.25 MHz and L is 2.84 microhenrys?
- A44 picofarads
- B2.2 microfarads
- C44 microfarads
- D2.2 picofarads
Correct answer: A — 44 picofarads. From the official ISED question bank, verified word for word.
Why
At resonance, the inductive and capacitive effects cancel each other out, meaning the circuit behaves as if it only has resistance. The full explanation — and one for every question — is in Pro.
Practise this section
Advanced theory is section A-001 of the Advanced exam: Advanced theory: time constants, reactance, impedance, resonance, Q, and the mathematics behind tuned circuits.
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