Advanced Qualification · A-001 Advanced theory · A-001-004-001
What is the resonant frequency of a parallel RLC circuit if R is 4.7 kilohms, L is 1 microhenry and C is 10 picofarads?
- A 15.9 kHz
- B 50.3 kHz
- C 15.9 MHz
- D 50.3 MHz
Correct answer: D — 50.3 MHz. From the official ISED question bank, verified word for word.
Why
The resonant frequency depends only on the inductor and capacitor values, not the resistor, so you plug 1 microhenry and 10 picofarads into the standard formula to find the result is 50.3 MHz. 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.