Advanced Qualification · A-001 Advanced theory · A-001-001-009
What is the time constant of a circuit having a 470 microfarad capacitor in series with a 470 kilohm resistor?
- A 470 seconds
- B 221 seconds
- C 221 000 seconds
- D 47 000 seconds
Correct answer: B — 221 seconds. From the official ISED question bank, verified word for word.
Why
The time constant is found by multiplying the resistance in ohms by the capacitance in farads. 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.