AC impedance & phasors worksheet with answers

Free printable AC impedance & phasors worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy
Vf = ?L = 500 mH

At what frequency f does a 500 mH inductor have a reactance of 1000 Ω?

L = 500 mHXL = 1000 Ω
f = Hz
2.Easy
24 V50 HzR = 10 ΩL = 100 mH

A series RL circuit is connected to a 24 V (rms), 50 Hz supply. Find the magnitude of the impedance |Z|.

V = 24 V (rms)f = 50 HzR = 10 ΩL = 100 mH
|Z| = Ω
3.Medium
Vf0​ = 1000 HzRL = 5 mHC = ?

A series RLC circuit with L = 5 mH must resonate at 1000 Hz. Find the capacitance C needed.

f0 = 1000 HzL = 5 mH
C = µF
4.Medium
Vf0​ = 50 HzRL = 100 mHC = ?

A series RLC circuit with L = 100 mH must resonate at 50 Hz. Find the capacitance C needed.

f0 = 50 HzL = 100 mH
C = µF
5.Hard
1 Vf0​R = 15 ΩL = 200 mHC = 2.2 µF

A series RLC circuit is driven by a 1 V (rms) source whose frequency is set to the resonant frequency of the circuit. Find the rms voltage VL across the inductor.

V = 1 V (rms)R = 15 ΩL = 200 mHC = 2.2 µF
VL = V
6.Hard
120 V500 HzR = 80 ΩL = 20 mHC = 2.2 µF+−VC​

A series RLC circuit is connected to a 120 V (rms), 500 Hz supply. Find the rms voltage VC across the capacitor.

V = 120 V (rms)f = 500 HzR = 80 ΩL = 20 mHC = 2.2 µF
VC = V

Answer key

  1. 1. f = 318.3 Hz
  2. 2. |Z| = 32.97 Ω
  3. 3. C = 5.066 µF
  4. 4. C = 101.3 µF
  5. 5. VL = 20.1 V
  6. 6. VC = 151.7 V

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