Advanced Qualification · A-001 Advanced theory · A-001-001-010
What is the time constant of a circuit having a 220 microfarad capacitor in series with a 470 kilohm resistor?
- A 470 000 seconds
- B 470 seconds
- C 220 seconds
- D 103 seconds
Correct answer: D — 103 seconds. From the official ISED question bank, verified word for word.
Why
The time constant equals 103 seconds because you multiply the resistance of 470 kilohms by the capacitance of 220 microfarads, converting the units so they cancel out to leave seconds. 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.