# Basic Electrical Engineering Expected MCQ PDF1 For Coal India Limited (CIL) MT Exam 2017

Question   #1

The main advantages of a.c. is ??.
A                 A.C. motors are
expensive
B                 The A.C. voltage
can’t be raised or lowered
C                 A.C. transmission is
very costly
D                 None
Correct Answer is Option D : None
Question   #2
The main advantage of purely sinusoidal waveform is??.
A                 it is only
alteranating waveform
B                 it is the only
standard waveform.
C                 any other waveform
can be resolved into series of sinusoidal waveforms of different frequency
D                 it produces distorted
waveforms when applied.
Correct Answer is Option C : any other
waveform can be resolved into series of sinusoidal waveforms of different
frequency
Question   #3
The waveforms in which magnitude changes but its direction remain same is
called ?
A                 pulsating d.c.
B                 alternating
C                 pure d.c.
D                 None
Correct Answer is Option A : pulsating
d.c.
Question   #4
??. Is the advantage of a.c.
A                 the voltage can be
raised or lowered
B                 A.C. transmission is
economical and efficient.
C                 A.C.can easily
converted to D.C.
D                 All of the above.
Correct Answer is Option D : All of the
above.
Question   #5
The generation of the a.c. is according to ??.
B                 Thevenins theorem
C                 Ohms law
D                 Kirchhoffs law
Question   #6
??..represents maximum value of alternating emf
A                 B I l
B                 B v l
C                 B I v
D                 l I v
Correct Answer is Option A : B I l
Question   #7
Standard alternating emf is represented as??.
A                 Em tan_
B                 Em cos_
C                 Em sin_
D                 None
Correct Answer is Option C : Em sin_
Question   #8
Standard alternating emf achieves its positive maximum value at _=??.
A                 45
B                 90
C                 180
D                 270
Correct Answer is Option B : 90
Question   #9
The time taken by an alternating quantity to complete one cycle is called??.
A                 Frequency
B                 Speed
C                 Waveform
D                 Time period
Correct Answer is Option D : Time period
Question   #10
The unit of frequency is ____
B                 Sec
C                 Hz
D                 Volts
Correct Answer is Option C : Hz
Question   #11
The relation between f and w is????
A                 f=1/w
B                 w=2?/f
C                 w=2?f
D                 w=1/f
Correct Answer is Option C : w=2?f
Question   #12
The time period of sinusoidal waveform with 200Hz frequency is??..
A                 0.005s
B                 0.0005s
C                 0.5s
D                 None
Correct Answer is Option C : 0.5s
Question   #13
The value of a alternating quantity of a particular instant is called??..value.

A                 Instantaneous
B                 Peak
C                 Peak to peak
D                 Average
Correct Answer is Option A : Instantaneous

Question   #14
The waveform which shows repetation of variations after a regular time interval
is called???
A                 Nonperiodic waveform
B                 Sawtooth waveform
C                 Periodic waveform
D                 Triangular waveform
Correct Answer is Option C : Periodic
waveform
Question   #15
In our nation, the standard frequency of alternating voltage is????.
A                 60 cycle/sec
B                 50 cycle/sec
C                 100 cycle/sec
D                 None
Correct Answer is Option B : 50 cycle/sec
Question   #16
The higher value attained by an alternating quantity during positive or
negative half cycle is called???..
A                 Maximum
B                 Amplitude
C                 Peak
D                 All
Correct Answer is Option B : Amplitude
Question   #17
For 50Hz alternating waveform the angular frequency is?????.rad/sec
A                 314.16
B                 50
C                 0.126
D                 None
Correct Answer is Option A : 314.16
Question   #18
An a.c voltage is given by v=40 sin 314t. The frequency is?????..
A                 75Hz
B                 50Hz
C                 25Hz
D                 100Hz
Correct Answer is Option B : 50Hz
Question   #19
An alternating voltage is given by v =100 sin (3.14 t-300) volts. The frequency
is ????
A                 25Hz
B                 50Hz
C                 60Hz
D                 100Hz
Correct Answer is Option B : 50Hz
Question   #20
An A.C. voltage is given by 100 sin 314 t. the frequency is????
A                 50Hz
B                 75Hz
C                 25Hz
D                 100Hz
Correct Answer is Option B : 75Hz
Question   #21
The equation of an alternating quantity is v = 282.84 sin 100 ? t then its
r.m.s value is???..
A                 200
B                 20
C                 141.421
D                 400
Correct Answer is Option A : 200
Question   #22
The voltage of domestic a.c. supply is 230V. This value represent???.
A                 Peak value
B                 r.m.s. value
C                 Average value
D                 Mean value
Correct Answer is Option B : r.m.s. value
Question   #23
The voltmeter in a.c. circuit always measures????.values.
A                 Average
B                 Maximum
C                 r.m.s.
D                 None
Correct Answer is Option A : Average
Question   #24
The r.m.s value of an alternating current is 10A then its peak to peak value is
____
A                 10A
B                 30A
C                 5A
D                 20A
Correct Answer is Option C : 5A
Question   #25
A sinusoidal voltage is represented as 141.42 sin 314 _t then its r.m.s value
of the voltage and frequency are respectively????
A                 141.42V, 314Hz
B                 100V, 50Hz
C                 100V, 60Hz
D                 200V, 100Hz
Correct Answer is Option B : 100V, 50Hz
Question   #26
The peak value of an alternating current is Im then its average value is????.
A                 0.637 Im
B                 4.12 Im
C                 1.44 Im
D                 None
Correct Answer is Option A : 0.637 Im
Question   #27
The average value of sinusoidal varying voltage is ?.. than its rms value.
A                 more
B                 less
C                 same as
D                 None
Correct Answer is Option A : more
Question   #28
The form factor of purely sinusoidal waveform is ?..
A                 1.11
B                 1.21
C                 1.414
D                 None
Correct Answer is Option A : 1.11
Question   #29
The peak factor of a sinusoidally varying voltage is ??..
A                 1.414
B                 1.11
C                 0.866
D                 0.707
Correct Answer is Option B : 1.11
Question   #30
Alternating quantities are represented by
A                 Vectors
B                 Scalars
C                 Phasors
D                 Graphs
Correct Answer is Option C : Phasors
Question   #31
Phasors always rotate in________ direction
A                 Clockwise
B                 Anticlockwise
C                 Vertical
D                 Horizontal
Correct Answer is Option B : Anticlockwise

Question   #32
_________ projection of a phasor reprents an instantaneous value of an
alternating quantity
A                 Y-axis
B                 X-axis
C                 Z-axis
D                 None
Correct Answer is Option B : X-axis
Question   #33
The phase of an alternating quantity varies from
A                 0-90
B                 0-180
C                 0-360
D                 180-360
Correct Answer is Option C : 0-360
Question   #34
When two alternating quantities are in phase then their phase difference
is________
A                 30
B                 90
C                 0
D                 60
Correct Answer is Option C : 0
Question   #35
The negative maximum of a cosine wave occurs at ???.
A                 45
B                 90
C                 180
D                 270
Correct Answer is Option C : 180
Question   #36
?????.. representation gives rms value of an alternating quantity
A                 Phasor
B                 Polar
C                 Rectangular
D                 None
Correct Answer is Option A : Phasor
Question   #37
The polar form of -3+j4 is???..
A                 5<-53.13
B                 5<53.13
C                 5<-126.86
D                 5<126.86
Correct Answer is Option D : 5<126.86
Question   #38
The rectangular form of the 5<30 is ???..
A                 4.33+j2.5
B                 4.33-j2.5
C                 Can’t say
D                 None
Correct Answer is Option A : 4.33+j2.5
Question   #39
For a 50Hz transformer, the primary turns are 100 and maximum flux in the core
is 0.08Wb then primary side induced emf is?????..
A                 1856V
B                 1276V
C                 1776V
D                 7776V
Correct Answer is Option C : 1776V
Question   #40
RMS value of the induced emf per turn in transformer is ????
A                 4f_m
B                 4.44f_m
C                 2f_m
D                 f_m
Correct Answer is Option B : 4.44f_m
Question   #41
For transformer the induced emf on primary is 199.8 V with 50 turns at 50 Hz
frequency than the maximum flux in the core is???..
A                 79.92mWb
B                 18mWb
C                 18Wb
D                 0.999Wb
Correct Answer is Option B : 18mWb
Question   #42
An ideal transformer is the one having?????..
A                 No losses
B                 Zero resistance
winding
C                 Zero leakage flux
D                 All
Correct Answer is Option D : All
Question   #43
For a 10 KVA 2000/200V transformer the half load secondary current is ??..
A                 50A
B                 5A
C                 25A
D                 2.5A
Correct Answer is Option C : 25A
Question   #44
If any ammeter in the secondary of a 100/10 V ratio reads 10 A ,The current the
primary would be ??..
A                 1A
B                 2A
C                 10A
D                 100A
Correct Answer is Option A : 1A
Question   #45
The transformer rating is expressed in VA because???..
A                 on both side it is
constant
B                 Losses are
C                 The frequency is
constant
D                 None
Correct Answer is Option B : Losses are
Question   #46
For 440 V /100V transformer the secondary turns are 16 than the primary turns
are ?????..
A                 4
B                 64
C                 26
D                 8
Correct Answer is Option A : 4
Question   #47
A transformer having turns ratio is 1:1 is called ???transformer
A                 Isolation
B                 Step up
C                 Step down
D                 None
Correct Answer is Option A : Isolation
Question   #48
A transformer has secondary full load current of 10A and secondary no load
induced emf of 200v then it is KVA rating is???..
A                 2000
B                 200
C                 2
D                 20
Correct Answer is Option C : 2
Question   #49
A high voltage side is ???..
A                 Low current, low
impedance side
B                 High current, low
impedence side
C                 Low current, high
impedance side
D                 None
Correct Answer is Option C : Low current,
high impedance side
Question   #50
A low voltage side is ???..
A                 Low current, low
impedance side
B                 High current, low
impedence side
C                 Low current, high
impedance side
D                 None
Correct Answer is Option B : High current,
low impedence side
Question   #51
Regulation of transformer is defined as ?..
A                 rise in terminal
B                 fall in terminal
C                 change in secondary
terminal volatage from no load to full load as a percentage of secondary no
D                 None
Correct Answer is Option C : change in
secondary terminal volatage from no load to full load as a percentage of
Question   #52
A                 Positive
B                 Negative
C                 Zero
D                 Unity
Correct Answer is Option B : Negative
Question   #53
For better performance of the transformer ,the regulation of the transformer
must be?.
A                 High
B                 Infinite
C                 Very low
D                 None
Correct Answer is Option C : Very low
Question   #54
the voltage regulation of the transformer is zero for ??.load
A                 Lagging
B                 Resistive
C                 Inductive
D                 Capacitive
Correct Answer is Option B : Resistive
Question   #55
If the transformer regulation is positive, ?..load is connected to the
transformer
A                 Capacitive
B                 Inductive
C                 Resistive
D                 None
Correct Answer is Option B : Inductive