Questions and answers for exam Preparation

MCQs

Total Questions : 327 | Page 27 of 33 pages

Question 261. The r.m.s. value of alternating current is given by steady (D.C.) current which when flowing through a given circuit for a given time produces__________?

the more heat than produced by A.C. when flowing through the same circuit
the same heat as produced by A.C. when flowing through the same circuit
the less heat than produced by A.C. flowing through the same circuit
none of the above

Discuss Question

Answer: Option B. -> the same heat as produced by A.C. when flowing through the same circuit
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 262. In a pure resistive circuit__________?

current lags behind the voltage by 90°
current leads the voltage by 90°
current can lead or lag the voltage by 90°
current is in phase with the voltage

Discuss Question

Answer: Option D. -> current is in phase with the voltage
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 263. The transient currents are associated with the____________?

changes in the stored energy in the inductors and capacitors
impedance of the circuit
applied voltage to the circuit
resistance of the circuit

Discuss Question

Answer: Option A. -> changes in the stored energy in the inductors and capacitors
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 264. In a circuit containing R, L and C, power loss can take place in____________?

C only
L only
R only
all above

Discuss Question

Answer: Option C. -> R only
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 265. In the case of an unsymmetrical alternating current the average value must always be taken over__________?

unsymmetrical part of the wave form
the quarter cycle
the half cycle
the whole cycle

Discuss Question

Answer: Option D. -> the whole cycle
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 266. In a pure inductive circuit___________?

the current is in phase with the voltage
the current lags behind the voltage by 90°
the current leads the voltage by 90°
the current can lead or lag by 90°

Discuss Question

Answer: Option B. -> the current lags behind the voltage by 90°
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 267. The power factor at resonance in R-L- C parallel circuit is________?

zero
0.08 lagging
0.8 leading
unity

Discuss Question

Answer: Option D. -> unity
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 268. When an alternating current passes through an ohmic resistance the electrical power converted into heat is__________?

apparent power
true power
reactive power
none of the above

Discuss Question

Answer: Option B. -> true power
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 269. In each of the three coils of a three phase generator, an alternating voltage having an r.m.s. value of 220 V is induced. Which of the following values is indicated by the voltmeters ______?