Q.91 The two alternating current IAand IB are said to be out of phase with each other if the phase difference between them is ___ (leading or lagging).
A. 180º or 2л
B. 180º or л
C. 360º or л
D. 180º or 0º
Ans.: B
Q.92 which of the following pair is true of form factor of alternating current?
A. perfect sinusoidal wave = 1.11= full wave rectified
B. half wave rectified = 1.57
C. rectangular wave = 1
D. all of the above
Ans. D
Q.93 which of the following is correct for average value alternating current?
A. perfect sinusoidal wave = 0.636 maximum value = full wave rectified
B. half wave rectified = 0.318 maximum value
C. rectangular wave = 1 maximum value
D. all of the above
Ans.: D
Q.94 which of the following is true of rms value of alternating current?
A. full wave rectified = perfect sinusoidal wave = 0.707 maximum value
B. rectangular wave = 1
C. triangular wave = 0.578 maximum value
D. all of the above
Ans.: D
Q.95 which of the following is correct?
A. form factor of triangular wave = 1.16
B. rms value of half wave rectified = 0.5 maximum value
C. average value of triangular wave = 0.5maximum value
D. all of the above
Ans.: D
Q.96 The values of peak factor for perfect sinusoidal and full wave rectified alternating current is ___.
A. √2
B. √5
C. √3
D. 2
Ans.: A
Q.97 The value of crest factor of half wave rectified, rectangular wave and triangular wave of alternating current is give as:
A. 2.0, 1, √3
B. √2, 1, √3
C. 2.0, 1, √3
D. √2, 1, 3
Ans.: C
Q.98 If the phase angle in equation V = Vm sin (Ѳ±ф) is positive then the phase difference is said to be___.
A. leading
B. lagging
C. in phase
D. any of the above
Ans.: A
Q.99 If the phase angle in equation V = Vm sin (Ѳ±ф) is negative then the phase difference is said to be___.
A. lading
B. in phase
C. lagging
D. none of the above
Ans.: C
Q.100 Consider, VA = Vm sin Ѳ and VB = Vm sin (Ѳ+ф)
Which of the following is true?
A.VAleads the voltage VB
B. VAlags behind VB by ф
C. VBleads the voltage VA
D. Both B and C
Ans.: D
Q.101 Give: v1 = 10 sin ωt, v2 = 20 sin (ωt- л/4), v3 = 30 cos (ωt + л/6)
Find the resultant voltage.
A.9.14 +j 11.84Volts
B. 9.14 +j 1.184Volts
C. 91.4 +j 11.84Volts
D. 91.4 +j 1.184Volts
Ans.: A
Q.102 which of the following wave has the highest value of form factor?
A. Half wave rectified sine wave
B. square wave
C. Triangular wave
D. Rectangular wave
Ans.: A
Q.103 The form factor of DC supply voltage is
A. always infinite
B. always zero
C. always 0.5
D. always unity
Ans.: D
Q.104 _____ wave has the least value of form factor.
A. Triangular wave
B. square wave
C. sine wave
D. Rectangular wave
Ans.: B
Q.105 The positive maximum value of sine wave __.
A. occurs at 45º
B. occurs at 0º
C. occurs at 180º
D. occurs at 90º
Ans.: D
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