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
50 V50 HzR = 25 ΩL = 200 mH

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

V = 50 V (rms)f = 50 HzR = 25 ΩL = 200 mH
|Z| = Ω
2.Easy
Vf = ?L = 50 mH

At what frequency f does a 50 mH inductor have a reactance of 20 Ω?

L = 50 mHXL = 20 Ω
f = Hz
3.Medium
120 V60 HzR = 20 ΩL = 50 mHC = 100 µF

A series RLC circuit is connected to a 120 V (rms), 60 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 120 V (rms)f = 60 HzR = 20 ΩL = 50 mHC = 100 µF
φ = °
4.Medium
10 V1000 HzR = 40 ΩL = 100 mHC = 4.7 µF

A series RLC circuit is connected to a 10 V (rms), 1000 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 10 V (rms)f = 1000 HzR = 40 ΩL = 100 mHC = 4.7 µF
φ = °
5.Hard
230 V1000 HzR = 100 ΩL = 250 mHC = 22 µF

A series RLC circuit is connected to a 230 V (rms), 1000 Hz supply. Find the resonant frequency f0 of the circuit.

V = 230 V (rms)f = 1000 HzR = 100 ΩL = 250 mHC = 22 µF
f0 = Hz
6.Hard
120 V200 HzR1​ = 20 ΩR2​ = 150 ΩC = 4.7 µFI

A resistor R1 is connected in series with a parallel combination of R2 and a capacitor C, across a 120 V (rms), 200 Hz supply. Find the rms current I.

V = 120 V (rms)f = 200 HzR1 = 20 ΩR2 = 150 ΩC = 4.7 µF
I = A

Answer key

  1. 1. |Z| = 67.62 Ω
  2. 2. f = 63.66 Hz
  3. 3. φ = −21 °
  4. 4. φ = 86.15 °
  5. 5. f0 = 67.86 Hz
  6. 6. I = 0.938 A

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