Advanced Qualification · A-001 Advanced theory · A-001-003-010
What is the resonant frequency of a series RLC circuit, if R is 47 ohms, L is 1 microhenry and C is 9 picofarads?
- A 1.77 MHz
- B 53.1 MHz
- C 5.31 MHz
- D 17.7 MHz
Correct answer: B — 53.1 MHz. From the official ISED question bank, verified word for word.
Why
The resonant frequency of 53.1 MHz is correct because it is the specific point where the inductor and capacitor cancel each other out, leaving only the 47 ohm resistor to oppose the flow. The full explanation — and one for every question — is in Pro.
Practise this section
Advanced theory: time constants, reactance, impedance, resonance, Q, and the mathematics behind tuned circuits.