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1
1. Permeance is inversely related to
(A) Resistance (B) Conductance
(C) Reluctance (D) Capacitance
Key: (C)
2. Consider the following statements regarding
an ideal core material:
1. It has very high permeability.
2. It loses all its magnetism when there is no
current flow.
3. It does not saturate easily.
Which of the above statements are correct?
(A) 1 and 2 only (B) 1 and 3 only
(C) 2 and 3 only (D) 1, 2 and 3
Key: (D)
3. The capacitance of a conducting sphere of
radius r with a total charge of q uniformly
distributed on its surface is
(A) Proportional to qr
(B) Independent of r
(C) Proportional to q
r
(D) Independent of q
Key: (D)
Sol: For a conducting sphere of radius R
Capacitance 0C 4 R, which is
independent of q
4. The characteristic impedance of a
transmission line depends upon
(A) Shape of the conductor
(B) Surface treatment of the conductor
(C) Conductivity of the material
(D) Geometric configuration of the conductor
Key: (D)
5. In a series R L C circuit supplied by a
source of 125 V at a resonant frequency of
220 Hz, the magnitudes of the voltages across
the capacitor and the inductor are found to be
4150 V. If the resistance of the circuit is1 ,
then the selectivity of the circuit is
(A) 33.20 (B) 3.32
(C) 0.0301 (D) 0.301
Key: (A)
Sol: Selectivity = r
2 1
f
f f
fr → Resonance frequency
f1 and f2 are 3db frequencies on either side
of fr
Resonancefrequency
Selectivity3 dbbandwidth
Selectivity is also equal to CL
R R
VVor
V V
CL
CL
R R
L c
R
XXQ or
R R
VVor
V V
At resonance,V 1250,V 4150
V 125(at resonance voltage
appearsresistance)
4150Q 33.2
125
6. The value of characteristic impedance in free
space is equal to
(A) 0
0
(B) 0 0
(C) 0 0
1
(D) 0
0
Key: (A)
EE-Objective Paper-I (2016)
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2
Sol: 0
0
7. The magnitude of magnetic field strength H
is independent of
(A) Current only
(B) Distance only
(C) Permeability of the medium only
(D) Both current and distance
Key: (C)
Sol: Permeability of medium
8. Consider the following types of transmission
lines:
1. Open-wire line
2. Twin-lead wire
3. Coaxial cable
The capacitance per metre will be least in
which of the above transmission lines?
(A) 1 only (B) 2 only
(C) 3 only (D) 1,2 and 3
Key: (A)
9. Three equal point charges are located at the
vertices of an equilateral triangle on the
circumference of a circle of radius r . The total
electric field intensity at the centre of the
circle would be
(A) Zero (B) 2
0
3q
4 r
(C) 2
0
q
12 r (D)
0
q
3 r
Key: (A)
Sol:
Electric field due to any two charges will
cancel the electric field due to third charge.
Then net electric field will be zero.
10. The Poynting vector on the surface of a long
straight conductor of radius a and
conductivity 0 , which carries current I in the
z-direction, is
(A) 2
r3
0
Ia
b (B)
2
r2 2
0
Ia
2 a
(C) 2
r2 3
0
Ia
a (D)
2
r2 3
0
Ia
2 a
Key: (D)
11. Consider the following application in respect
of a square corner reflector:
1. Radio astronomy
2. Point-to-point communication
3. TV broadcast
Which of the above applications is/are
correct?
(A) 1 only (B) 1 and 2 only
(C) 2 and 3 only (D) 1, 2 and 3
Key: (D)
12. The variation of B with distance r from a
very ling straight conductor carrying a current
I is correctly represented by
(A)
(B)
r
B
r
B
q q
q
rr
r
q q
q
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3
(C)
(D)
Key: (D)
Sol: 1
B αr
13. The resistivity of hard drawn copper at 20 C
is 61.9 10 cm . The resistivity of annealed
copper compared to hard drawn copper is
(A) Lesser (B) Slightly larger
(C) Same (D) Much larger
Key: (A)
14. The number of electrons excited into the
conduction band from valence band (with
E forbidden energy gap and k Boltz-
mann‟s constant) is proportional to
(A) E
expkT
(B) 2 E
expkT
(C) E
expkT
(D) 2 E
expkT
Key: (C)
Sol: The intrinsic carriers are the electron which
will move to conduction band from valence
band. The intrinsic carrier concentration is
given by,
G
T
E
K2
i C Vn N N e
Thus the excited electron concentration is
proportional to GE
KTGe ;HereB E
15. Superconductivity in a material can be
destroyed by
1. Increasing the temperature above a
certain limit
2. Applying a magnetic field above a certain
limit.
3. Passing a current above a certain limit.
4. Decreasing the temperature to a point
below the critical temperature.
Which of the above are correct?
(A) 1 and 2 only (B) 2 and 3 only
(C) 1, 2 and 3 only (D) 1, 2, 3 and 4
Key: (C)
16. The relative permeability of a medium is
equal to (with M = magnetization of the
medium and H = magnetic field strength)
(A) M
1H
(B) M
1H
(C) M
1H
(D) M
1H
Key: (A)
17. The electrical resistivity of many metals and
alloys drops suddenly to zero when they are
cooled to a low temperature (i.e., nearly equal
to liquid helium temperature). Such materials
(metals and alloys) are known as
(A) Piezoelectric materials
(B) Diamagnetic materials
(C) Superconductors
(D) High-energy hard magnetic materials
Key: (C)
18. The dielectric strength of rubber is 40000
V/mm at frequency of 50 Hz. What is the
thickness of insulation required on an
electrical conductor at 33 kV to sustain the
breakdown?
(A) 0.83 mm (B) 8.3 mm
(C) 8.3 cm (D) 0.083 mm
r
B
r
B
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4
Key: (A)
Sol: We know the electric field is given by
3
vE
d
v 33 10d 0.825mm
E 40,000
0.83mm
19. The conductivity of insulating materials
(a very small value) is called as
(A) Residual conductivity
(B) Dielectric conductivity
(C) Ionic conductivity
(C) bipolar conductivity
Key: (C)
20. An intrinsic semiconductor has equal number
of electrons and holes in it. This is due to
(A) Doping (B) free electrons
(C) Thermal energy (D) Valence electrons
Key: (C)
Sol: Intrinsic carriers are generated by thermal
energy
21. When a very small amount of higher
conducting metal is added to a conductor, its
conductivity will
(A) Increase
(B) Decrease
(C) Remain the same
(D) Increase of decrease depending on the
impurity.
Key: (B)
22. An electrically balanced atom has 30 protons
in its nucleus and 2 electrons in its outermost
shell. The material made of such atom is
(A) a conductor
(B) an insulator
(C) a semiconductor
(D) a superconductor
Key: (A)
Sol: Number of proton in a nucleus always
indicates the atomic number, So the element
having atomic number 30. So Zinc is the
element, which is a conductor.
23. The temperature coefficient of resistance of a
doped semiconductor is
(A) Always positive
(B) Always negative
(C) Zero
(D) Positive or negative depending upon the
level of doping
Key: (D)
24. In the slice processing of an integrated circuit
(A) Components are formed in the areas
where silicon dioxide remains
(B) Components are formed in the areas
where silicon dioxide has been removed.
(C) The diffusing elements diffuse through
silicon dioxide
(D) Only on diffusion process is used
Key: (B)
Sol: Thick oxide layer on the surface of substrate
is removed by a process called photo-
lithography and component regions are placed
into those window regions.
25. Permanent magnet loses the magnetic
behaviour when heated because of
1. Atomic vibration
2. Dipole vibration
3. Realignment of dipoles
Which of the above are correct?
(A) 1 and 2 only (B) 1 and 3 only
(C) 1, 2 and 3 (D) 2 and 3 only
Key: (C)
26. The magnetic field required to reduce the
residual magnetization to zero is called
(A) Retentivity (B) Coercivity
(D) Hysteresis (D) Saturation
Key: (B)
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5
27. A certain fluxmeter has the following
specifications:
Air gap flux density 20.05 wb / m
Number of turns on moving coil = 40
Area of moving coil = 2750 mm
If the flux linking 10 turns of a search coil of
200 2mm area connected to the fluxmeter is
reversed in a uniform field of 20.5 Wb / m ,
then the deflection of the fluxmeter will be
(A) 87.4 (B) 76.5
(C) 65.6 (D) 54.7
Key: (B)
Sol: Constant of flux meter = G = NBA
6 6G 40 0.05 750 10 1500 10
Flux linking with coil 60.5 200 10
6100 10 Wb
Change in flux linking with coil = 62 100 10 (As flux meter is reversed)
6200 10
Change in flux, G N
N G
6
6
o
10200 10
1500 10
4rad 76.5
3
28. Consider the following statements:
1. Both ferromagnetic and ferrimagnetic
materials have domain structures; each
domain has randomly oriented magnetic
moments when no external field is
applied.
2. Both ferromagnetic and ferrimagnetic
materials make those domains that have
favourable orientation to the applied field
grow in size.
3. The net magnetic moment in
ferromagnetic material is higher than that
in ferrimagnetic material.
4. The net magnetic moment in
ferrimagnetic material is higher than that
in ferromagnetic material.
Which of the above statements are correct?
(A) 1 and 4 only (B) 1, 2 and 4 only
(C) 2 and 4 only (D) 1, 2 and 3
Key: (D)
Sol: Ferrimagnetism
The magnetism is a result of the alignment of
tiny regions in the material called “magnetic
domains” or "magnetic moments" in the
material. For ferrimagnetism, neighboring
magnetic moments lie in opposite directions.
Normally, the opposite ordering cancels out
the overall magnetic field of an object;
however, in a ferrimagnet, small differences
between neigboring domains makes a
magnetic field possible.
Ferromagnetism
Ferromagnetism occurs in some elements
such as iron, nickel and cobalt. In these
elements, the magnetic moments align in the
same direction and parallel to each other to
produce strong permanent magnets. Recently,
rare earth elements such as neodymium have
been found to greatly intensify
ferromagnetism, resulting in powerful,
compact permanent magnets.
Some magnetic domains in a ferrimagnetic
material point in the same direction and some
in the opposite direction. However, in
ferromagnetism they all point in the same
direction. For a ferromagnet and a ferrimagnet
of the same size, therefore, the ferromagnet
will likely have a stronger magnetic field.
29. The Hall voltage, HV , for a thin copper plate
of 0.1 mm carrying a current of 100 A with
the flux density in the z-direction,
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6
2
zB 1Wb / m and the Hall coefficient,
11 3
HR 7.4 10 m / C , is
(A) 148 V (B) 111 V
(C) 74 V (D) 37 V
Key: (C)
Sol: Relation between Hall voltage & Hall
coefficient is given by,
HH
Z
3 11 3
H
2
Z
311 H
11
H 4
5
H
V WR
B I
W 0.1 10 m;R 7.4 10 m / C
B 1 Wb / m ;I 100A
V 0.1 107.4 10
1 100
7.4 10 100V
10
V 7.4 10 74 v
30. A Zener regulator has an input voltage
varying between 20 V and 30 V. The desired
regulated voltage is 12 V, while the load
varies between 140 and10 k . The
maximum resistance in series with the
unregulated source and Zener diode would be
(A) 3.3 (B) 6.6
(C) 36.6 (D) 93.3
Key: (D)
Sol:
Z LV 12V R 140to10K
Vi 20to30V R ?? maximumvalue
To get maximum resistance, input voltage
must be low and output resistance (RL) low.
Hence
ZI K 0A not given
ZL
L
L
i Z
L
V 12I 0.08A
R 140
I I 0.08A
V V 20 12R 100
I I 0.08
31. A short in any type of circuit (series, parallel
or combination) causes the total circuit
1. Resistance to decrease
2. Power to decrease
3. Current to increase
4. Voltage to increase
Which of the above are correct?
(A) 2 and 3 (B) 2 and 4
(C) 1 and 4 (D) 1 and 3
Key: (D)
32. An air-cooled solenoid of 250 turns has a
cross-sectional area
2A 80cm and length l 100cm. The value
of its inductance is
(A) 0.425 mH (B) 0.628 mH
(C) 0.751 mH (D) 0.904 mH
Key: (B)
Sol: Given N = 250; A = 80cm2=80×10
-4m
2
l =100cm=100×10-2
m
L=Inductance of air cored solenoid = 2
0N A
2 4 7
2
250 80 10 4 10L 0.628mH
100 10
33. The current in a coil changes uniformly from
10 A to 1 A in half a second. A voltmeter
connected across the coil gives a reading of
36 V. The self-inductance of the coil is
(A) 0.5H (B) 1H (C) 2H (D) 4H
Key: (C)
Sol: di = change of current = 10-1=9A
dt = change of time = 0.5sec
RILI
zViV 20to30VLR
140to10K
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7
eL=Voltage across inductor = 36V
eL= di
L ;dt
Le 36 36L L 2H
di 9 18
dt 0.5
34. In a mutually coupled circuit, the primary
current is reduced from 4 A to zero in10 s . A
voltage of 40000 V is observed across the
secondary. The mutual inductance between
the coils is
(A) 100 H (B) 10H (C) 0.1H (D) 0.01H
Key: (C)
Sol: 1di 4 0 4A
6
2
112 L 12
L12 6
1
dt 10 10 sec
e 40000V
diM ?; e M
dte 40000
M 0.1Hdi 4 /10 10
dt
35. N resistors each of resistance R when
connected in series offer an equivalent
resistance of 50 and when reconnected in
parallel the effective resistance is 2 . The
value of R is
(A) 2.5 (B) 5
(C) 7.5 (D) 10
Key: (D)
Sol: Given
s pR 50 ; R 2
s
p
R NR NR 50
50R ... 1
N
R RR 2
N N
R 2N ... 2
2
Multiplying equations 1 and 2
50R 2N
N
R 100 10
36. For a series R-L circuit
i t 2 sin t 45 .
If L 1 , the value of R is
(A) 1 (B) 3
(C) 3 (D) 3 3
Key: (A)
Sol: Given i t 2 sin t 45
45 lag ; L 1
R ?
1 1L
1
X Ltan tan
R R
145 tan
R
1tan 45 1 R 1
R
37. A single-phase full-wave rectifier is construc-
ted using thyristors. If the peak value of the
sinusoidal input voltage is mV and the delay
angle is π/3 radian, then the average value of
output voltage is
(A) m0.32 V (B) m0.48 V
(C) m0.54 V (D) m0.71 V
Key: (B)
Sol: mo
om
o m m
VV (1 Cos )
V(1 Cos60 )
V 0.477V 0.48 V
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8
38. The potential difference ABV in the circuit
(A) 0.8 V (B) 0.8 V
(C) 1.8 V (D) 1.8 V
Key: (B)
Sol: At node A
AA
A A
BB
B B
AB A B
V 5V1 0
4 1
165V 16; V 3.2V
5
At node B,
V 5V1 0
3 3
2V 8; V 4V
V V V 3.2 4 0.8V
39. Two bulbs of 100 W/250 V and 150 W/250 V
are connected in series across a supply of 250
V. The power consumed by the circuit is
(A) 30 W (B) 60 W
(C) 100 W (D) 250 W
Key: (B)
Sol: Given 1 2P 100w; P 150w
T
1 2T
1 2
P ?
P P 100 150P 60W
P P 250
40. Thevenin‟s equivalent of a circuit, operating
at 5 rad / s , has
OC
O
V 3.71 15.9 V
z 2.38 j 0.667
At this frequency, the minimal realization of
the Thevenin‟s impedance will have
(A) A resistor, a capacitor and an inductor.
(B) A resistor and a capacitor
(C) A resistor and an inductor
(D) A capacitor and an inductor
Key: (B)
Sol: Z0=Thevenin‟s Impedance = 2.38- j 0.667Ω
0 cZ R jx
Minimal realization will be with R and C
41. Analog-to-digital converter with the minimum
number of bits that will convert analog input
signals in the range of 0-5 V to an accuracy of
10 mV is
(A) 6 (B) 9 (C) 12 (D) 15
Key: (B)
Sol: n
fullscalereadingAccuracy
2
n n 2
3
n
5V2 2 5 10
10 10 V
2 500 n 9
42. Three 30 resistors are connected in parallel
across an ideal 40 V source. What would be
the equivalent resistance seen by the load
connected across this circuit?
(A) 0 (B) 10 (C) 20 (D) 30
Key: (A)
Sol:
To find Req, Voltage source is short circuited.
eqR 0
ABV
1A
1
4
3
3
5 V
BV
AV
eqR
3030
eqR
303040V
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9
43. The current i(t) through a 10 resistor in
series with an inductance is given by
i t 3 4sin 100t 45
4sin 300t 60 A
The RMS value of the current and the power
dissipated in the circuit are respectively
(A) 5 A and 150 W (B) 11 A and 250 W
(C) 5 A and 250 W (D) 11 A and 150 W
Key: (C)
Sol:
2 2
rms rms1 rms2
2 2
2
rms
rms
2 2
rms
I I I ........
4 4I 3
2 2
I 25 5A
P I R 5 10 250W
44. Thevenin‟s equivalents of the network in
Fig.(i) are 10 V and 2 . If a resistance of
3 is connected across terminals AB as
shown in fig. (ii), what are Thevenin‟s
equivalents?
(A) 10 V and 1.2 (B) 6 V and 1.2
(C) 10 V and 5.2 (D) 6 V and 5.2
Key: (B)
Sol:
Th
10 3V 6V
5
To fine RTh, Short circuit voltage source
Th
6R 1.2
5
45. A voltage source, connected to a load, has an
e.m.f. of 10 V and an impedance of
500 j100 . The maximum power that
can be transferred to the load is
(A) 0.2W (B) 0.1W
(C) 0.05W (D) 0.01W
Key: (C)
Sol: For maximum power transfer
*
L L
22
Thmax
L
Z Z
10VP 0.05W
4R 4 500
46. An ideal transformer is rated 220/110 V. A
source of 10 V and internal impedance of
2 is connected to the primary. The power
transferred to a load LZ connected across the
secondary would be a maximum, when LZ is
(A) 4 (B) 2 (C) 1 (D)0.5
Key: (D)
47. Consider the following values for the circuit
shown below:
o
o
A
B
o
o
A
B
3
Fig.(ii)Fig.(i)
3
2
A
B
10V
3
2
A
B
500 j100
LZ10V
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10
1. RV 100 2V
2. I = 2A
3. L = 0.25 H
Which of the above values are correct?
(A) 2 and 3 only (B) 1 and 2 only
(C) 1 and 3 only (D) 1, 2 and 3
Key: (*)
Sol: 2 2
R LV V V
2 2
R
R
L L
L
V 250 150 200V
V 200I 2A
R 100
V I.X I. L
V 150L 0.125H
I. 2 600
no option is correct
48. The response of a series R-C circuit is given
by
0q2V
CI S1
R sRC
where 0q is the initial
charge on the capacitor. What is the final
value of the current?
(A) 0q1 2V
R C
(B)
tRC
0qe 2V
R C
(C) Infinity (D) Zero
Key: (D)
Sol: Using the final value theorem
0
s 0 s 0
q2vs
Ci limSI s lim 0
1R s
RC
49. What should be done to find the initial values
of the circuit variables in a first-order R-C
circuit excited by only initial conditions?
(A) To replace the capacitor by a short
circuit.
(B) To replace the capacitor by an open
circuit.
(C) To replace the capacitor by a voltage
source.
(D) To replace the capacitor by a current
source.
Key: (C)
50. In a parallel resistive circuit, opening a branch
results in
1. Increase in total resistance
2. Decrease in total power
3. No change in total voltage and branch
voltage
Which of the above is/are correct?
(A) 1 only (B) 2 only
(C) 3 only (D) 1, 2 and 3
Key: (D)
51. The precision resistors are
(A) Carbon composition resistors
(B) Wire-wound resistors
(C) Resistors with a negative temperature
coefficient
(D) Resistors with a positive temperature
coefficient.
Key: (B)
52. In nodal analysis, the preferred reference node
is a node that is connected to
100
150 VRV
L v t =
250 2sin 600t
I
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11
1. Ground
2. Many parts of the network
3. The highest voltage source
Which of the above is/are correct?
(A) 1 only (B) 2 only
(C) 3 only (D) 1, 2 and 3
Key: (B)
53. Two networks are said to be dual when
(A) Their node equations of the same
(B) The loop equations of one network are
analogous to the node equations of the
other
(C) Their loop equations are the same
(D) The voltage sources of one network are
the current sources of the other
Key: (B)
54. Reciprocity theorem is applicable to a
network
1. Containing R, L and C elements
2. Which is initially not a relaxed system
3. Having both dependent and independent
sources
Which of the above is/are correct?
(A) 1 only (B) 1 and 2 only
(C) 2 and 3 only (D) 1, 2 and 3
Key: (A)
55. Which of the following is true for the
complete response of any network voltage or
current variables for a step excitation to a
first-order circuit?
(A) It has the form at
1k e
(B) It has the form k
(C) It may have either the form (a) or the
form of (a) plus (b)
(D) It has the form ate
Key: (C)
56. A piezoelectric crystal has a coupling
coefficient K of 0.32. How much electrical
energy must be applied to produce output
energy of 37.06 10 J?
(A) 25.38 mJ (B) 22.19 mJ
(C) 4.80 mJ (D) 2.26 mJ
Key: (B)
57. If a constant current generator of 5 A, shunted
by its own resistance of 1 , delivers
maximum power P in watts to its load of
LR , then the voltage across the current
generator and P are
(A) 5 V and 6.25 (B) 2.5 V and 12.5
(C) 5 V and 12.5 (D) 2.5 V and 6.25
Key: (D)
Sol: To, get maximum power transfer
L s LR R R 1
Then the circuit will be
By current division we can say that, the
current flowing through each resistor is
2.5Amp and voltage across current generator
is 2.5 1 2.5volts
LR15A
LR 1 15A
2.5A
5A 2.5A
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12
22 L
max L L
L
22
VP I R or
R
2.52.5 1 or
1
6.25 or 6.25watts
58. Three star-connected loads of 3 60 each
and three delta-connected loads of 9 60
each are connected in parallel and fed from a
three-phase balanced source having line-to-
neutral voltage of 120 V. The line currents
drawn from the supply will be
(A) 10 A each (B) 20 A each
(C) 80 A each (D) 160 A each
Key: (C)
Sol: Converting Delta connected load to Star
configuration, we get
o o9
60 3 603
Now fig (2) becomes
In the question it is given that fig (1) & fig (3)
are connected in parallel. Now when these
loads are connected in parallel, the equivalent
load is:
∴ line current voltage 120
80A3Impedance
2
59. A wattmeter reads 10 kW, when its current
coil is connected in R phase and the potential
coil is connected across R and neutral of a
balanced 400 V (RYB sequence) supply. The
line current is 54 A. If the potential coil
reconnected across B-Y phases with the
current coil in R phase, the new reading of the
wattmeter will be nearly
(A) 10kW (B) 13kW (C) 16kW (D) 19kW
Key: (B)
Sol: Case-I: When current coil is connected in R-
Phase and potential coil is connected across R
and neutral,
Watt meter reading,
RN R
3
P V I cos
40010 10 54 cos
3
cos 0.80
Case-II: When current coil is connected to R-
Phase and potential
coil between B and
Y phase.
o9 60
o9 60o9 60
Delta connected load
Fig : 2
o3 60
o3 60o3 60
Star connected load
Fig :1
o3 60
o3 60o3 60
Fig :3
o3 60
o3 60
o3 60
o3 60
o3 60o3 60
o360
2
o360
2
o360
2
RI
RV
YV
BV
RI
YVBV
BYV
RV
90
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13
Wattmeter reading
BY R
BY R
P | V | I | cos 90
V .I .sin 400 54 0.6
P 12.96 kW 13 kW
60. The phase voltage of a three-phase, star-
connected alternator is V. By mistake, the
connection of R phase got reversed. The new
line voltages will have a relationship.
(A) YBRY BR
VV V
3
(B) BRRY YB
VV V
3
(C) RYYB BR
VV V
3
(D) RY YB BRV V V
Key: (A)
Sol: Under normal conditions, phases are
displaced by 120o. But as „R‟
Phase is reversed, phasor diagram becomes
We can infer that, RY BR BY| V | | V | | V |
61. Two-wattmeter method of power measure-
ment in three-phase system is valid for
(A) Balanced star-connected load only
(B) Unbalanced star-connected load only
(C) Balanced delta-connected load only
(D) Balanced or unbalanced star- as well
Key: (D)
62. Consider the following statements regarding
the effect of adding a pole in the open-loop
transfer function on the closed-loop step
response:
1. It increases the maximum overshoot
2. It increases the rise time.
3. It reduces the bandwidth
Which of the above statements are correct?
(A) 1, 2 and 3 only (B) 1 and 2 only
(C) 2 and 3 only (D) 1 and 3 only
Key: (D)
63. A CRO screen has 10 divisions on the
horizontal scale. If a voltage signal
5sin 314t 45 is examined with line base
setting of 5 ms/div, the number of signals
displayed on the screen will be
(A) 1.25 cycles (B) 2.5 cycles
(C) 5 cycles (D) 10 cycles
Key: (B)
Sol: oV t 5 sin 314t 45
n=10 divisions on horizontal scale
f=50 HZ 1
T 20 msecf
Line base setting = 5 ms/div
Total time span = base setting × no. of
divisions
5 10 50 msec
50 msecNo.of Cycles 2.5cycle
20 msec
64. A series R L C circuit is connected to a
25 V source of variable frequency. The circuit
current is found to be a maximum of 0.5 A at
a frequency of 400 Hz and the voltage across
Y
R
B
Y
R
B
o60o60
5
o45
5
T
t
20msec
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14
C is 150 V. Assuming ideal components, the
values of R and L are respectively.
(A) 50 and 300 mH
(B) 12.5 and 0.119 H
(C) 50 and 0.119 H
(D) 12.5 and 300 mH
Key: (C)
Sol:
In a series RLC circuit current is maximum
when the circuit is operating under resonance
and is given by
supply
max
V 25I 0.5A R 50
R R
It is also given as CV 150V
C supplyV QV
C
supply
V 150VQ 6
V 25
0
0
L QR 6 50Q L
R 2 400
0.750.119H
2
65. The resonant frequency for the circuit
For L 0.2 H,R 1 and C 1 F , is
(A) 1 rad/s (B) 2 rad/s
(C) 3 rad/s (D) 4 rad/s
Key: (B)
Sol:
eq 22
2 22 2
1j C
1 Rz j L j L1 1j C CR R
1C Rj L
1 1C C
R R
For resonance imaginary component must
be zero
2
2 2
2 2 2 2
2 2
2
2 2
2
CL
1C
R
1 C C 1C C
R L L R
1 1
LC R C
1 1 11 5 1 2
LC 0.2RC
66. Which one of the following conditions will be
correct, when three identical bulbs forming a
star are connected to a three-phase balanced
supply?
(A) The bulb in R phase will be the brightest
(B) The bulb in Y phase will be the brightest
(C) The bulb in B phase will be the brightest
(D) All the bulb will be equally bright.
Key: (D)
67. For the two-port network shown in the figure
L
C R
1I
1V
2I
2V
0.5AR L
150V
~25cos t, 400Hz
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15
1 1 2 2 1 2V 60I 20I and V 20I 40I .
Consider the following for the above network:
1. The network is both symmetrical and
reciprocal.
2. The network is reciprocal.
3. A D
4. 11
1y
50
Which of the above is/are correct?
(A) 2 only (B) 2 and 4 only
(C) 1 only (D) 1 and 3 only
Key: (B)
Sol: From the given 2 equation we can write the Z
parameter matrix as
60 20
Z20 40
Since 11 22Z Z it is said to be asymmetrical
12 21Z Z it is said to be reciprocal.
So 1 is not correct we can eliminate option C
& D.
→ Now to confirm whether A, B, we need to
find Y11
1
11
40 201Y Z
20 6040 60 20 20
40 40 1Y
2400 400 2000 50
So2 & 4 are correct
68. If the total powers consumed by three
identical phase loads connected in delta and
star configurations are 1 2W and W respecti-
vely, then 1W is
(A) 23W (B) 2W
3 (C) 23W (D) 2W
3
Key: (A)
Sol: In delta connection power consumed = W1
In Star connection power consumed = W2
1 2W 3W
69. A 100 A ammeter has an internal resistance
of 100 . For extending its range to measure
500 A , the required shunt resistance is
(A) 10 (B) 15 (C) 20 (D) 25
Key: (D)
Sol: m mI 500 A, I 100 A,R 100
msh
m
sh
R I 500R ;m 5
m 1 I 100
100 100R 25
5 1 4
70. A 200 V PMMC voltmeter is specified to be
accurate within 2% of full scale. The
limiting error, when the instrument is used to
measure a voltage of 100 V, is
(A) 8% (B) 4% (C) 2% (D) 1%
Key: (B)
Sol: Full scale deflection = SA 200V
Accuracy = 2% of full scale
r oMagnitude of limiting error, A A
0.02 200 4V
% limiting error 4
100 4%100
71. How many poles does the following function
have?
3
2
s 2s 1F s
s 3s 2
(A) 0 (B) 1 (C) 2 (D) 3
Key: (C)
A 100 A
100
shR
500 A
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16
72. The degree to which an instrument indicates
the changes in measured variable without
dynamic error is
(A) Repeatability (B) Hysteresis
(C) Precision (D) fidelity
Key: (D)
73. Loading by the measuring instruments
introduces an error in the measured
parameter. Which of the following devices
gives the most accurate results?
(A) PMMC (B) Hot-wire
(C) CRO (D) Electrodynamic
Key: (C)
Sol: CRO has the higher input impedance than
PMMC, hot wire and electrodynamic
instruments and hence errors in the measured
parameters due to loading effect will be
lesser.
74. A moving-coil galvanometer can be used as a
DC ammeter by connecting
(A) A high resistance in series with the meter
(B) A high resistance across the meter
(C) A low resistance across the meter
(D) A low resistance in series with the meter
Key: (C)
75. Consider the following types of damping:
1. Air-friction damping
2. Fluid-friction damping
3. Eddy-current damping
PMMC type instruments use which of the
above?
(A) 1 only (B) 2 only
(C) 3 only (D) 1, 2 and 3
Key: (C)
76. In data acquisition system, analog data
acquisition system is used
(A) For narrow frequency width, while digital
data acquisition system is used when
wide frequency width is to monitored.
(B) For wide frequency width, while digital
data acquisition system is used when
narrow frequency width is to monitored.
(C) When quantity to be monitored varies
slowly, while its counterpart is preferred
if the quantity to be monitored varies
very fast.
(D) When quantity to be monitored is time-
variant, while digital data acquisition
system is preferred when quantity is
time-invariant.
Key: (B)
77. During the measurement of resistance by
Carey Foster bridge, no error is introduced
due to
1. Contact resistance
2. Connecting leads
3. Thermoelectric e.m.f.
(A) 1 and 2 only (B) 1 and 3 only
(C) 2 and 3 only (D) 1 ,2 and 3
Key: (D)
78. Schering bridge is a very versatile AC bridge
and is used for capacitor testing in terms of
1. Capacitance value (magnitude)
2. Loss angle measurement
3. Simple balance detector like PMMC
instrument
4. Providing safety to operators by
incorporating Wagner earthing device
Which of the above are correct?
(A) 1 and 3 only (B) 3 and 4 only
(C) 1,2 and 4 only (D) 1,2,3 and 4
Key: (C)
79. Consider the following instruments:
1. MI instrument
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17
2. Electrostatic instrument
3. Electrodynamometer instrument
Which of the above instruments is/ are free
from hysteresis and eddy-current losses?
(A) 1 only (B) 2 only
(C) 3 only (D) 1,2 and 3
Key: (B)
80. Dummy strain gauges are used for
(A) Compensation of temperature changes
(B) Increasing the sensitivity of bridge
(C) Compensating for different expansions
(D) Calibration of strain gauge.
Key: (A)
81. A wattmeter is measuring the power supplied
to a circuit whose power factor is 0.7. The
frequency of the supply is 50 c/s. The
wattmeter has a potential coil circuit of
resistance 1000 and inductance 0.5 H. The
error in the meter reading is
(A) 4% (B) 8% (C) 12% (D) 16%
Key: (C)
Sol: cos 0.7, 45.57
p Potentialcoil
P
LP
f 50Hz
R 1000 Z 1000 j157
L 0.5H
X L 2 fL 314 0.5 157
%error tan tan B 100
157tan 45.57 100 16.015%
1000
82. A moving-coil instrument gives full-scale
deflection of 10 mA, when a potential
difference of 10 mV is applied across its
terminals. To measure currents up to 100 A,
the same instrument can be used
(A) With shunt resistance of 0.0001
(B) With series resistance of 0.01
(C) With shunt resistance of 0.01
(D) With series resistance of 0.0001
Key: (A)
Sol:
3
m
msh
I 100m 10000
I 10 10
R 1R 0.0001
m 1 10000 1
83. A 400 V, three-phase, rated frequency
balanced source is supplying power to a
balanced three-phase load carrying a line
current of 5 A at an angle of 30 lagging. The
readings of the two wattmeters 1W and 2W ,
used for measuring the power drawn by the
circuit, are respectively.
(A) 2000 W and 1000 W
(B) 1500 W and 1500 W
(C) 2000 W and 1500 W
(D) 1500 W and 1000 W
Key: (A)
Sol: Total power, L LP 3 V I cos
3 400 5 cos30
Total Power = 3000 watts
From the given options (a) & (b) denotes
3000 watts, but from the option „b‟, both W1
& W2 are equal. So W1 & W2 are only same
when there is unity power factor. Hence
option „a‟ is right answer.
84. A current of 4 3 2 sin t 30 A is
passed through a centre zero PMMC meter
and a moving-iron meter. The two meters will
read respectively.
(A) 4 A and 5 A (B) 4 A and 5 A
(C) 4 A and 5 A (D) 4 A and 5 A
10mA
1
shR100A
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Key: (C)
Sol: PMMC Meter reads average value or DC
value
PMMC reads - 4 A
Moving Iron meter reads RMS value
2
2
RMS
RMS
3 2i 4
2
i 16 9 25 5A
85. A structural member is compressed to
produce a strain of 5 m / m . The nickel wire
strain gauge has a gauge factor of -12.1. The
pre-stress resistance of the gauge is 120 .
The change in resistance due to compressive
strain will
(A) Increase the resistance by 7.26m
(B) Decrease the resistance by 7.26m
(C) Increase the resistance by 49.6m
(D) Decrease the resistance by 49.6m
Key: (A)
Sol: Guage factor R / R
strain
6
6
Rstrain Guagefactor
R
R5 10 12.1
R
R 5 10 12.1 120
R 7.26 m
As strain guage is of negative value, the
change in resistance due to compressive strain
will decrease the resistance by 7.26 m .
86. The values of ammeter and voltmeter
resistances are 0.1 and 200 respectively
as shown in the figure below. The percentage
error in the calculated value of R 100
(voltmeter reading 200 V/ammeter reading 2
A) is nearly
(A) -2% (B) -5% (C) 2% (D) 5%
Key: (B)
Sol: Percentage error V
R100%
R
200V / 2A
100 5%2000
In the given circuit, voltmeter measures true
value of voltage but the Ammeter measures
sum of currents through resistance &
voltmeter
msh
m
sh
RR
m 1
R 1000m 1 5
R 200
m 1 5 m 6
87. What is the multiplying power of a shunt of
200 resistance when used with a
galvanometer of 1000 resistance?
(A) 4 (B) 6 (C) 12 (D) 20
Key: (B)
Sol:
sh
m
sh m
R 1000
R 200
R m 1 R
1000 m 1 200
m 6
88. The mesh-current method
1. Works with both planar and non-planar
circuits
2. Uses Kirchoff‟s voltage law
VR 2000
AR 0.1 R
V
A
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Which of the above is/are correct?
(A) 1 only (B) 2 only
(C) Both 1 and 2 (D) Neither 1 nor 2
Key: (B)
89. An 8-bit successive approximation A-to-D
converter is driven by a 2 MHz clock. Its
conversion time is
(A) 18 s (B) 16 s
(C) 8 s (D) 4.5 s
Key: (D)
Sol: A n bit successive approximation ADC takes
n cycles for conversion.
As it is 8-bit
8 clock cycles for conversion
time6
18 4 sec
2 10
90. In using instrument transformers, care should
be taken not to open circuit the
(A) Primary of a voltage transformer when
the secondary is connected to the rated
load.
(B) Secondary of a voltage transformer when
the primary is energized with the rated
voltage.
(C) Primary of a current transformer when
the secondary is connected to the rated
load.
(D) Secondary of a current transformer when
the primary is carrying the rated current.
Key: (D)
91. An inverse z-transform x kT of
aT
aT
1 eX z
z 1 z e
is
(A) akT1 e (B) akT1 e
(C) akT1 e (D) akT1 e
Key: (*)
Sol: Given X (z) =
aT
aT
1 e
z 1 z e
(None of the option satisfying)
92. A system has a transfer function
2
C s 4
R s s 1.6s 4
for a unit-step response and 2% tolerance
band, the settling time will be
(A) 5 seconds (B) 4 seconds
(C) 3 seconds (D) 2 seconds
Key: (A)
Sol:
s
2
n
2 2 2
n n
n
s
100 100ln ln
4x% 2t
wn wn wn
C s w4
R s S 1.6S 4 S 2 w s w
1.6w 0.8
2
t 5seconds.
93. Consider the following statements with
reference to the response of a control system:
1. A large resonant peak corresponds to a
small overshoot in transient response.
2. A large bandwidth corresponds to slow
response.
3. The cut-off rate indicates the ability of
the system to distinguish the signal from
noise.
4. Resonance frequency is indicative of the
speed of transient response.
Which of the above statements are correct?
(A) 1 and 2 only (B) 2 and 3 only
(C) 1 and 4 only (D) 1 and 3
Key: (D)
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20
94. The open-loop transfer of a unity feedback
system is
K
s s 4. For a damping factor of
0.5, the value of the gain K must be set to
(A) 1 (B) 2 (C) 4 (D) 16
Key: (D)
Sol: 2
n
n
2
n
C(S) K
R(S) S 4S K
2 4
4
K 16
95. For a unity feedback control system, the
forward path transfer function is given by
2
40G s
s s 2 s 2s 30
The steady-state error of the system for the
input 25t
2is
(A) 0 (B) (C) 220t (D) 230t
Key: (B)
Sol:
2
2
ss aS 0
a
2
a 2S 0
ss
40Gcd type1
S(S 2) S 2S 30
Ae K 1imS G(s)
K
40K 0 lim S . 0
S S 2 S 2S 50
e
96. When gain K of the open-loop transfer
function of order greater than unity is varied
from zero to infinity, the closed-loop system
(A) May become unstable
(B) Stability may improve
(C) Stability may not be affected
(D) Will become highly stable
Key: (A)
97. The frequency of sustained oscillation for
marginal stability, for a control system
2KG s H s
s s 1 s 5
and operating
with negative feedback, is
(A) 5r / s (B) 6r / s
(C) 5 r / s (D) 6 r / s
Key: (A)
Sol:
3 2
2KG(s)H(S)
S S 1 S 5
1 G S H S S S 1 S 5 2K
S 6S 5S 2K 0
For marginally stable, we need find frequency
of oscillation
3 2S 6S 5S 2K 0
3
2
1
0
S 1 5
30 2KS 6 2K 0
6
30 2KS 0 K 15
6
S 2K 0
Now we get that K = 15
2
2
So, 6S 2 K 0
6S 30 0
W 5 rad / sec
98. Consider the following statements:
1. Adding a zero to the G(s)H(s) tends to
push root locus to the left.
2. Adding a pole to the G(s)H(s) tends to
push root locus to the right.
3. Complementary root locus (CRL) refers
to root loci with positive K.
4. Adding a zero to the forward path
transfer function reduces the maximum
overshoot of the system.
Which of the above statements are correct?
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21
(A) 1, 2 and 3 only (B) 3 and 4 only
(C) 1,2 and 4 only (D) 1,2,3 and 4
Key: (C)
99. An R-C network has the transfer function
2
C 2
s 10s 24G s
s 10s 16
. The network could be
used as
1. lead compensator
2. lag compensator
3. lag-lead compensator
Which of the above is/are correct?
(A) 1 only (B) 2 only
(C) 3 only (D) 1,2 and 3
Key: (C)
Sol: 2
c 2
S 10S 24G S
S 10S 16
S 4 S 6
S 2 S 8
Lead lag
Gc (S) → will work as lead lag compensation
100. The partial fraction expansion of the function
2
3 2
4z 2zF z
z 5z 8z 4
is
(A)
2
2 12
z 1 z 2
(B)
2
2 2 12
z 1 z 2 z 2
(C)
1.5 12
z 1 z 1 z 2
(D)
2
1.5 1.5 1
z 1 z 2 z 2
Key: (B)
Sol: We can actually solve this question by using
option we will get the solution as
2
23 2
4z 2z 2 2 12
z 5z 8z 4 z 1 z 2 z 2
101. If an energy meter makes 5 revolutions in 100
seconds, when a load of 225 W is connected,
the meter constant is
(A) 800 rev/kWh (B) 222 rev/kWh
(C) 147 rev/kWh (D) 13 rev/kWh
Key: (A)
Sol: Energy supplied in watt hour
100225 hr
3600
225W hr 0.0625 kWh
36
No.of revolutionsMeterconstant
kwh
5800 rev / kWh
0.0625
102. In a closed-loop control system
(A) Control action is independent of output
(B) Output is independent of input
(C) There is no feedback
(D) Control action is dependent on output
Key: (D)
103. The characteristics polynomial of a system
can be defined as
(A) Denominator polynomial of given
transfer function
(B) Numerator polynomial of given transfer
function
(C) Numerator polynomial of a closed-loop
transfer function
(D) Denominator polynomial of a closed-loop
transfer function
Key: (D)
Sol: Denominator polynomial of a closed loop
transfer function
104. For a critically damped system, the closed-
loop poles are
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22
(A) Purely imaginary
(B) Real, equal and negative
(C) Complex conjugate with negative real
part
(D) Real, unequal and negative
Key: (B)
Sol: Real, equal, and negative
105. A second-order position control system has an
open-loop transfer function
57.3K
G ss s 10
. What value of K will result
in a steady-state error of1 , when the input
shaft rotates at 10 r.p.m.?
(A) 21.74 (B) 10.47 (C) 5.23 (D) 0.523
Key: (B)
o
o
2
ss
v
Vs 0
57.3KG s H s
S s 10
10 360input 10rpm t.u(t)
60
r(t)input 60 t.u(t)
60R s
S
60Steadystate error e 1
K
57.3KK lim S 57.3K
S S 10
601 K 10.47
5.73K
106. Gain margin is the factor by which the system
gain can be increased to drive it to
(A) Stability
(B) Oscillation
(C) The verge of instability
(D) Critically damped state
Key: (C)
107. Nichols‟ chart is used to determine
(A) Transient response
(B) Closed-loop frequency response
(C) Open-loop frequency response
(D) Setting time due to step input
Key: (B)
108. For a type-I system, the intersection of the
initial slope of the Bode plot with 0 dB axis
give
(A) Steady-state error
(B) Error constant
(C) Phase margin
(D) Cross-over frequency
Key: (A)
109. The desirable features of a servomotor are
(A) Low rotor inertia and low bearing friction
(B) High rotor inertia and high bearing
friction
(C) Low rotor inertia and high bearing
friction
(D) High rotor inertia and low bearing
friction
Key: (A)
Directions:
Each of the following eleven (11) items
consists of two statements, one labelled as
‘Statement (I)’ and the other as ‘Statement
(II)’. Examine these two statements carefully
and select the answers to these items using the
code given below:
Codes:
(A) Both Statement (I) and Statement (II) are
individually true and Statement (II) is the
correct explanation of Statement (I).
(B) Both Statement (I) and Statement (II) are
individually true but Statement (II) is not
the correct explanation of Statement (I).
ESE-2016 ESE-2016 |EE| Objective Paper-I
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23
(C) Statement (I) is true but Statement (II) is
false.
(D) Statement (I) is false but Statement (II) is
true.
110. Statement (I):
For type-II or higher systems, lead
compensator may be used.
Statement (II):
Lead compensator increases the margin of
stability.
Key: (A)
111. Statement (I):
Stability of a system deteriorates when
integral control is incorporated into it.
Statement (II):
With integral control action, the order of a
system, more the system tends to become
unstable.
Key: (A)
112. Statement (I):
Self-loops can exist in block diagram but not
in signal flow graph.
Statement (II):
Both block diagrams and signal flow graphs
are applicable to linear time-invariant
systems.
Key: (C)
113. Statement (I):
The gauge factor of a strain gauge is the ratio
of strain to per unit change in resistance.
Statement (II):
Poisson‟s effect is defined as producing less
strain with opposite sign on the plane
perpendicular to the applied load.
Key: (D)
Sol: Gauge factor = ratio of relative change in
electrical resistance R to the mechanical strain
R
RGF
114. Statement (I):
Voltage is the energy per unit charge created
by charge separation.
Statement (II):
Power is energy per unit of time.
Key: (B)
115. Statement (I):
The electrical conductivity of a solid solution
alloy drops off rapidly with increased alloy
content.
Statement (II):
A solid solution has a less regular structure
than a pure metal.
Key: (A)
116. Statement (I):
In type-0 and type-1 systems, stable operation
is possible if gain is suitably reduced.
Statement (II):
Any one of the compensators lag, lead, lag-
end may be used to improve the performance.
Key: (B)
117. Statement (I):
Open-loop system is inaccurate and unreliable
due to internal disturbances and lack of
adequate calibration.
Statement (II):
Closed-loop system is inaccurate as it cannot
account environmental or parametric changes
and may become unstable.
Key: (C)
ESE-2016 ESE-2016 |EE| Objective Paper-I
ICP–Intensive Classroom Program IES-Live Internet Based Classes DLP All India IES-Test Series Leaders in IES Preparation 65+ Centers across India
© All rights reserved by Gateforum Educational Services Pvt. Ltd. No part of this booklet may be reproduced or utilized in any form without the written permission.
24
118. Statement (I):
A constant temperature type hot-wire
anemometer is suitable for turbulent flow
measurements.
Statement (II):
When the resistance of the hot wire is kept
constant by incorporating current feedback,
the bandwidth is increased.
Key: (A)
119. Statement (I):
Optical pyrometers are used as transducers for
the measurement of flame temperature in a
boiler.
Statement (II):
Non-invasive methods are suitable for flame
temperature measurement in a boiler.
Key: (A)
120. Statement (I):
The null voltage of an LVDT cannot be
reduced to an insignificant value.
Statement (II):
Hall effect transducers are primarily used to
measure flux density.
Key: (D)