Series AC Circuits MCQ Questions Answers Electrical Engineering

Series AC Circuits Electrical Engineering MCQ Questions Answers

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

a) phasor

b) vector quantity

c) scalar quantity

d) none of the above

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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

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

a) 0

b) 1

c) -1

d) none of the above

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4) A series resonant circuit magnifies …………

a) voltage

b) current

c) both voltage and current

d) none of the above

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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

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

a) L/CR

b) RL/C

c) L/C

d) R/L

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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

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

a) 90⁰

b) 0⁰

c) 60⁰

d) 180⁰

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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

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

a) 90⁰

b) 30⁰

c) 45⁰

d) cannot be predicted