Advanced Qualification · A-001 Advanced theory · A-001-003-003
What is the resonant frequency of a series RLC circuit, if R is 47 ohms, L is 50 microhenrys and C is 10 picofarads?
- A7.12 kHz
- B3.18 MHz
- C3.18 kHz
- D7.12 MHz
Correct answer: D — 7.12 MHz. From the official ISED question bank, verified word for word.
Why
The resonant frequency is 7.12 MHz because the formula depends only on the inductor and capacitor values, while the 47 ohm resistor does not change the frequency at which they balance. 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.
Drill A-001 — free, no account