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 = 200 mH

At what frequency f does a 200 mH inductor have a reactance of 500 Ω?

L = 200 mHXL = 500 Ω
f = Hz
2.Easy
Vf = ?L = 500 mH

At what frequency f does a 500 mH inductor have a reactance of 100 Ω?

L = 500 mHXL = 100 Ω
f = Hz
3.Medium
50 V500 HzR = 30 ΩL = 100 mHC = 1 µFI

A series RLC circuit is connected to a 50 V (rms), 500 Hz supply. Find the rms current I.

V = 50 V (rms)f = 500 HzR = 30 ΩL = 100 mHC = 1 µF
I = A
4.Medium
230 V500 HzR = 15 ΩL = 100 mHC = 10 µF

A series RLC circuit is connected to a 230 V (rms), 500 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 230 V (rms)f = 500 HzR = 15 ΩL = 100 mHC = 10 µF
φ = °
5.Hard
VfR = 5 ΩL = 10 mHC = 0.47 µF

A series RLC circuit has R = 5 Ω, L = 10 mH and C = 0.47 µF. Find its quality factor Q at resonance.

R = 5 ΩL = 10 mHC = 0.47 µF
Q =
6.Hard
12 Vf0​R = 50 ΩL = 10 mHC = 1 µF

A series RLC circuit is driven by a 12 V (rms) source whose frequency is set to the resonant frequency of the circuit. Find the rms voltage VL across the inductor.

V = 12 V (rms)R = 50 ΩL = 10 mHC = 1 µF
VL = V

Answer key

  1. 1. f = 397.9 Hz
  2. 2. f = 31.83 Hz
  3. 3. I = 1.651 A
  4. 4. φ = 86.96 °
  5. 5. Q = 29.17
  6. 6. VL = 24 V

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