Time Response of Reactive Circuits — Engineering Board Exam Practice Questions

25 free engineering board exam reviewer questions on Time Response of Reactive Circuits (AC Circuits), each with the correct answer and a worked solution.

  1. A 10, F capacitor charged to 50 V is connected through a resistor across an identical uncharged 10, F capacitor. How much energy is…
  2. An RC circuit has a time constant of 0.1 s. After the switch connects it to a dc source, how long does the (initially uncharged) capacitor…
  3. A 5, F capacitor charged to 100 V discharges through a 2 M resistor. What is the capacitor voltage 10 s after the discharge begins?
  4. The capacitor in the circuit shown already holds 6 V (same polarity as the source) when the switch closes at t=0 (V=24 V, R=10 k , C=10…
  5. In the circuit shown the capacitor is uncharged and the switch closes at t=0 (V=30 V, R1=2 k , R2=3 k , C=10, F). Find the capacitor…
  6. A 0.2 H coil carrying 2 A is suddenly switched so that its current must flow through a total resistance of 50, (no source). What is the…
  7. If the resistance in a series RC charging circuit is doubled while C is unchanged, the time constant
  8. In an RC charging circuit, the current at t=3 is what percentage of the initial current?
  9. A 100, F capacitor charged to 100 V discharges through a 10 k resistor. How long does it take for the voltage to fall to 10 V?
  10. A 100, resistor is in series with a 0.5 H inductor and a dc source. After the switch closes, how long does it take for the current to…
  11. How much energy is stored in the magnetic field of a 2 H inductor carrying 0.5 A?
  12. How much energy is stored in a 100, F capacitor charged to 24 V?
  13. The curve shows the capacitor voltage after a switch connects an uncharged capacitor in series with a 2 k resistor to a dc source. The…
  14. The switch in the RL circuit shown closes at t=0 with no initial current (V=6 V, R=100, , L=200 mH). Find the voltage across the inductor…
  15. The switch in the RL circuit shown closes at t=0 with no initial current (V=24 V, R=40, , L=4 H). Find the current at t=100 ms.
  16. The capacitor shown is charged to 50 V when the switch closes at t=0 and discharges through R=20 k (C=22, F). Find the capacitor voltage…
  17. The switch in the circuit shown closes at t=0 with the capacitor uncharged (V=48 V, R=10 k , C=2, F). Find the circuit current at t=60 ms.
  18. The capacitor in the circuit shown is initially uncharged and the switch closes at t=0 (V=48 V, R=2 k , C=10, F). How long does it take…
  19. The switch in the circuit shown closes at t=0 with the capacitor initially uncharged (V=24 V, R=20 k , C=500 nF). Find the capacitor…
  20. At the instant a switch connects an uncharged capacitor to a dc voltage source through a resistor, the capacitor behaves like a
  21. What percentage of its final value has a charging capacitor voltage reached after one time constant?
  22. After how many time constants is a charging capacitor generally considered to be fully charged?
  23. The switch in the series RL circuit shown closes at t=0 (V=15 V, R=50, , L=1 H). Find the time constant.
  24. In the circuit shown the capacitor is uncharged when the switch closes at t=0 (V=30 V, R=5 k , C=10, F). What current flows in the circuit…
  25. The switch in the circuit shown closes at t=0 with the capacitor initially uncharged. The source is 6 V, R=10 k , and C=1, F. Find the…