Alternating Current

Topics in this chapter

• Alternating Voltage and Current
• Peak, Average, and RMS Values
• Phasors and Phase Relations
• Reactance and Impedance
• Series LCR Circuits and Resonance
• AC Power and Power Factor
• Transformers and Energy Transfer

Cheat sheet

Practice questions

1. Question 1Q-1610ED

   The root-mean-square (rms) value of an alternating current of peak value I0 is:

   1. A.I0
   2. B.I0 / sqrt(2)
   3. C.I0 / 2
   4. D.sqrt(2) I0
   See the answer and solution
2. Question 2Q-DE0053

   The average value of a sinusoidal alternating current over one complete cycle is:

   1. A.I0 / sqrt(2)
   2. B.2 I0 / pi
   3. C.Zero
   4. D.I0
   See the answer and solution
3. Question 3Q-4EDCCB

   The average (mean) value of a sinusoidal alternating current over one half-cycle is:

   1. A.I0 / sqrt(2)
   2. B.2 I0 / pi
   3. C.I0 / 2
   4. D.pi I0 / 2
   See the answer and solution
4. Question 4Q-C9ADC1

   The inductive reactance X_L of an inductor of inductance L at angular frequency omega is:

   1. A.omega L
   2. B.1 / (omega L)
   3. C.L / omega
   4. D.omega / L
   See the answer and solution
5. Question 5Q-23EE35

   The capacitive reactance X_C of a capacitor of capacitance C at angular frequency omega is:

   1. A.omega C
   2. B.1 / (omega C)
   3. C.C / omega
   4. D.omega / C
   See the answer and solution