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
V400 HzL = 5 mH

Find the reactance XL of a 5 mH inductor at 400 Hz.

L = 5 mHf = 400 Hz
XL = Ω
2.Easy
Vf = ?L = 20 mH

At what frequency f does a 20 mH inductor have a reactance of 25 Ω?

L = 20 mHXL = 25 Ω
f = Hz
3.Medium
50 V500 HzR = 20 ΩL = 50 mHC = 100 µFI

A series RLC circuit is connected to a 50 V (rms), 500 Hz supply. Find the real power P taken from the supply.

V = 50 V (rms)f = 500 HzR = 20 ΩL = 50 mHC = 100 µF
P = W
4.Medium
12 V200 HzR = 20 ΩL = 250 mHC = 22 µFI

A series RLC circuit is connected to a 12 V (rms), 200 Hz supply. Find the rms current I.

V = 12 V (rms)f = 200 HzR = 20 ΩL = 250 mHC = 22 µF
I = A
5.Hard
120 V200 HzR1​ = 20 ΩR2​ = 50 ΩC = 47 µF

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 magnitude of the impedance |Z|.

V = 120 V (rms)f = 200 HzR1 = 20 ΩR2 = 50 ΩC = 47 µF
|Z| = Ω
6.Hard
5 Vf0​R = 10 ΩL = 10 mHC = 1 µF

A series RLC circuit is driven by a 5 V (rms) source whose frequency is set to the resonant frequency of the circuit. Find the rms voltage VL across the inductor.

V = 5 V (rms)R = 10 ΩL = 10 mHC = 1 µF
VL = V

Answer key

  1. 1. XL = 12.57 Ω
  2. 2. f = 198.9 Hz
  3. 3. P = 2.076 W
  4. 4. I = 0.04306 A
  5. 5. |Z| = 29.38 Ω
  6. 6. VL = 50 V

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