Advanced Qualification · A-001 Advanced theory · A-001-003-007
What is the resonant frequency of a series RLC circuit, if R is 47 ohms, L is 8 microhenrys and C is 7 picofarads?
- A2.13 MHz
- B21.3 MHz
- C28.4 MHz
- D2.84 MHz
Correct answer: B — 21.3 MHz. From the official ISED question bank, verified word for word.
Why
The correct value of 21.3 MHz comes from applying the standard formula for resonance, where the inductance and capacitance values determine the frequency at which the circuit naturally oscillates. 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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