Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

AC CIRCUITS > PART 2 > Flashcards

PART 2 Flashcards

1
Q
  1. If emf in a circuit is given by e = 100 sin 628t, the maximum value of voltage and frequency are

A. 100 V, 50 Hz

B. 50√2 V, 50 Hz

C. 100 V, 100 Hz

D. 50√2 V, 100 Hz

A

C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q
  1. When the sole purpose of an alternating current is to produce heat, the selection of conductor is based on

A. average value of current

B. peak value of current

C. rms value of current

D. any of the above

A

C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q
  1. The form factor of dc supply voltage is always

A. infinite

B. zero

C. 0.5

D. unity

A

A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q
  1. The frequency of a sinusoidal signal shown in figure is

EE Question Banks figure no. 54
A. 500 Hz

B. 1 kHz

C. 25 kHz

D. 500 kHz

A

A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q
  1. The period of the voltage 2 cos 4500πt + 7 sin 7500πt is

A. 2.51 s

B. 2.51 ns

C. 2.51 ms

D. 2.51 μs

A

C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q
  1. The a.c. system is preferred to d.c. system because ______

A. a.c. voltages can easily be changed in magnitude

B. d.c. motors do not have fine speed control

C. high-voltage a.c. transmissions is less efficient

D. d.c. voltage cannot be used for domestic appliance

A

A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q
  1. In a.c. system, we generate sine wave form because ______

A. it can be easily drawn

B. it produces lest disturbance in electrical circuits

C. it is nature’s standard

D. other waves cannot be produced easily

A

B

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q
  1. ______ will work only on d.c. supply.

A. Electric lamp

B. Refrigerator

C. Heater

D. Electroplating

A

D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q
  1. ______ will produce a.c. voltage.

A. Friction

B. Photoelectric effect

C. Thermal energy

D. Crystal

A

D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q
  1. A coil is rotating in the uniform field of an 8-pole generator. In one revolution of the coil, the number of cycles generated by the voltage is ______.

A. one

B. two

C. four

D. eight

A

C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q
  1. An alternating voltage is given by v = 20 sin 157t. The frequency of the alternating voltage is ______.

A. 50 Hz

B. 25 Hz

C. 100 Hz

D. 75 Hz

A

B

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q
  1. An alternating current is given by i = 10 sin 314t. The time taken to generate two cycles of current is ______.

A. 0.02 second

B. 0.01 second

C. 0.04 second

D. 0.05 second

A

C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q
  1. An alternating voltage is given by v = 30 sin 314t. The time taken by the voltage to reach -30 V for the first time is ______.

A. 0.02 second

B. 0.1 second

C. 0.03 second

D. 0.015 second

A

D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q
  1. A sine wave has a maximum value of 20 V. Its value at 135° is _____.

A. 10 V

B. 14.14 V

C. 15 V

D. 5 V

A

B

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q
  1. A sinusoidal current has a magnitude of 3 A at 120°. Its maximum value will be ______.

A. √3 A

B. √3/2 A

C. 2√3 A

D. 6 A

A

C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q
  1. An alternating current given by i = 10 sin 314t. Measuring time from t = 0, the time taken by the current to reach +10 A for the second time is ______.

A. 0.05 second

B. 0.1 second

C. 0.025 second

D. 0.02 second

A

C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q
  1. An a.c. generator having 10 poles and running at 600 r.p.m. will generate an alternating voltage of frequency _______

A. 25 Hz

B. 100 Hz

C. 50 Hz

D. 200 Hz

A

C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q
  1. We have assigned a frequency of 50 Hz to power system because it ______

A. can easily be obtained

B. gives best result when used for operating both lights and machinery

C. leads to easy calculation

D. none of the above

A

B

19
Q
  1. An alternating voltage is given by v = 100 sin 314t volts. Its average value will be ______.

A. 70.7 V

B. 50 V

C. 63.7 V

D. 100 V

A

C

20
Q
  1. An alternating current whose average value is 1 A will produce ____ 1 A d.c. under similar conditions.

A. less heat than

B. more heat than

C. the same heat as

D. none of these

A

A

21
Q
  1. A sinusoidal alternating current has a maximum value of Im. Its average value will be ______.

A. Im/π

B. Im/2π

C. 2Im/π

D. none of these

A

C

22
Q
  1. The area of a sinusoidal wave over a half-cycle is ______

A. max. value /2

B. 2 x max. value

C. max. value /π

D. max. value /2π

A

B

23
Q
  1. An alternating voltage is given by v = 200 sin 314t. Its r.m.s. value will be ______

A. 100 V

B. 282.8 V

C. 141.4 V

D. 121.4 V

A

C

24
Q
  1. The r.m.s. value of sinusoidally varying current is _____ that of its average value.

A. more than

B. less than

C. same as

D. none of these

A

A

25
Q
  1. Alternating voltages and currents are expresses in r.m.s. values because ______

A. they can be easily determined

B. calculations become very simple

C. they give comparison with d.c.

D. none of these

A

C

26
Q
  1. The average value of sin2θ over a complete cycle is ______

A. +1

B. -1

C. ½

D. zero

A

C

27
Q
  1. The average value of sinθ over a complete cycle is ______.

A. zero

B. +1

C. -1

D. ½

A

A

28
Q
  1. An alternating current is given by i = Im sin θ. The average value of squared wave of this current over a complete cycle is ______

A. Im/2

B. Im/π

C. 2Im/π

D. 2Im

A

A

29
Q
  1. The form factor a sinusoidal wave is ______

A. 1.414

B. 1.11

C. 2

D. 1.5

A

B

30
Q
  1. The filament of a vacuum tube requires 0.4 A d.c. to heat it. The r.m.s. value of a.c. required is ______.

A. 0.4 x √2

B. 0.4 /2 A

C. 0.8 /√2

D. 0.4 A

A

D

31
Q
  1. A 100 V peak a.c. is as effective as ______ d.c.

A. 100 V

B. 50 V

C. 70.7 V

D. none of these

A

C

32
Q
  1. The form factor of a ______ wave is 1.

A. sinusoidal

B. square

C. triangular

D. saw tooth

A

B

33
Q
  1. Out of the following ______ wave is the peakiest.

A. sinusoidal

B. square

C. rectangular

D. triangular

A

D

34
Q
  1. The peak factor of a sine wave form is ______.

A. 1.11

B. 1.414

C. 2

D. 1.5

A

B

35
Q
  1. When a 15-V square wave is connected across a 50-V a.c. voltmeter, it will read ______.

A. 15 V

B. 15 x √2

C. 15 /√2

D. none of these

A

A

36
Q
  1. The breakdown voltage of an insulation depends upon _____ value of alternating voltage.

A. average

B. r.m.s.

C. peak

D. twice the r.m.s.

A

C

37
Q
  1. The peak factor of a half-wave rectified a.c. is ______.

A. 1.57

B. 2

C. 1.11

D. 1.4142

A

B

38
Q
  1. The form factor of a half-wave rectified a.c. is ______ .

A. 2

B. 1.11

C. 1.414

D. 1.57

A

D

39
Q
  1. When 200 V sinusoidal peak-to-peak is connected across an a.c. voltmeter, it will read ______

A. 141.4 V

B. 50 V

C. 70.7 V

D. none of these

A

C

40
Q
  1. The average value of a sinusoidal current is 100 A. Its r.m.s value is ______.

A. 63.7 A

B. 70.7 A

C. 141.4 A

D. 111 A

A

D

41
Q
  1. A current wave is given by i = 4 + 2√2 sin 3θ + 4√2 sin 5θ. The r.m.s. value of current wave is ______.

A. 10 A

B. 6 A

C. √56 A

D. 5 A

A

C

42
Q
  1. An alternating voltage or current is a ______.

A. scalar quantity

B. vector quantity

C. phasor

D. none of these

A

C

43
Q
  1. Three parallel circuits take the following currents: i1 = 5 sin 314t, i2 = 30 sin (314t + π/2) and i3 = 25 sin (314t – π/2). The expression for the resultant current is ______.

A. 25 sin (314t + π/3)

B. 5 sin (314t + π/2)

C. 10 sin (314t – π/6)

D. 5√2 sin (314t + π/4)

A

D

44
Q
  1. The sum of the following two e.m.f’s will be ______

e1 = 10 sin ωt e2 = 10 cos ωt

A. 10

B. 20 sin ωt

C. 14.14 cos ωt

D. 14.14 sin (ωt + π/4)

A

D

AC CIRCUITS (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions