Advanced Qualification · A-001 Advanced theory · A-001-004-010
What is the resonant frequency of a parallel RLC circuit if R is 4.7 kilohms, L is 90 microhenrys and C is 100 picofarads?
- A 1.77 kHz
- B 1.77 MHz
- C 1.68 kHz
- D 1.68 MHz
Correct answer: D — 1.68 MHz. From the official ISED question bank, verified word for word.
Why
The resonant frequency is 1.68 MHz because the resistance value does not change where the inductor and capacitor cancel each other out; only the inductance of 90 microhenrys and capacitance of 100 picofarads matter for this calculation. 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.