**Series AC Circuits Electrical Engineering MCQ Questions Answers**

1) **Impedance of an a.c. circuit is a ________________.**

a) phasor

b) vector quantity

c) scalar quantity

d) none of the above

2) **The active and apparent powers of an a.c. circuit are equal in magnitude. The circuit power factor is …….**

a) o.707

b) 0.5

c) 0.8

d)1

3) **The power factor of a.c. circuit is ………..**

a) 0

b) 1

c) -1

d) none of the above

4) **A series resonant circuit magnifies …………**

a) voltage

b) current

c) both voltage and current

d) none of the above

5) **The Q factor of a coil is given by ……..**

a) R/X_{L}

b) I/X_{L}

c) I/R

d) X_{L}/R

6) **Dynamic impedance of a parallel tuned circuit is …………**

a) L/CR

b) RL/C

c) L/C

d) R/L

7) **Power factor of a circuit can be improved by the use of**

a) choke coil

b) capacitor

c) induction motor

d) none of the above

8) **Wattless current is said of flow when phase angle between voltage and current is**

a) 90^{0}

b) 0^{0}

c) 60^{0}

d) 180^{0}

9) **In the above question, what is the true power supplied to the circuit ?**

a) 9 W

b) 18 W

c) 4.5 W

d) 36.8 W

10) **In an R-L series a.c. circuit XL=R. the phase angle is**

a) 90^{0}

b) 30^{0}

c) 45^{0}

d) cannot be predicted

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