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
12 V60 HzR = 10 ΩC = 22 µF

A series RC circuit is connected to a 12 V (rms), 60 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 12 V (rms)f = 60 HzR = 10 ΩC = 22 µF
φ = °
2.Easy
12 V50 HzR = 10 ΩL = 100 mH

A series RL circuit is connected to a 12 V (rms), 50 Hz supply. Find the magnitude of the impedance |Z|.

V = 12 V (rms)f = 50 HzR = 10 ΩL = 100 mH
|Z| = Ω
3.Medium
100 V100 HzR = 50 ΩL = 200 mHI

A resistor and an inductor are connected in parallel across a 100 V (rms), 100 Hz supply. Find the magnitude of the impedance |Z|.

V = 100 V (rms)f = 100 HzR = 50 ΩL = 200 mH
|Z| = Ω
4.Medium
120 V60 HzR = 25 ΩL = 100 mHC = 100 µFI

A series RLC circuit is connected to a 120 V (rms), 60 Hz supply. Find the real power P taken from the supply.

V = 120 V (rms)f = 60 HzR = 25 ΩL = 100 mHC = 100 µF
P = W
5.Hard
100 V60 HzR1​ = 25 ΩR2​ = 150 ΩC = 10 µFI

A resistor R1 is connected in series with a parallel combination of R2 and a capacitor C, across a 100 V (rms), 60 Hz supply. Find the rms current I.

V = 100 V (rms)f = 60 HzR1 = 25 ΩR2 = 150 ΩC = 10 µF
I = A
6.Hard
VfR = 10 ΩL = 50 mHC = 2.2 µF

A series RLC circuit has R = 10 Ω, L = 50 mH and C = 2.2 µF. Find its quality factor Q at resonance.

R = 10 ΩL = 50 mHC = 2.2 µF
Q =

Answer key

  1. 1. φ = −85.26 °
  2. 2. |Z| = 32.97 Ω
  3. 3. |Z| = 46.46 Ω
  4. 4. P = 480.1 W
  5. 5. I = 0.6543 A
  6. 6. Q = 15.08

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