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Q. No. 1 – 20 Carry One Mark Each

1. The pressure coil of a dynamometer type wattmeter is

(A) highly inductive (C) purely resistive
(B) highly resistive (D) purely inductive

2. The measurement system shown in the figure uses three sub-systems in cascade whose gains are specified
as G 1 , G 2 , and 1/G 3 . The relative small errors associated with each respective subsystem G 1 , G 2 and G 3
are ε 1 , ε 2 ,and ε 3 . The error associated with the output is
(A)
(B)
(C)
(D)

input G G2 1/G3 output

3. The following circuit has a source voltage V s as shown in the graph. The current through the circuit is
also shown.
a b

+
Vs R 10k
-

1.5
15
10 1
Current (mA)

5 0.5
Vs (Volts)

0 0
-0.5
-5
-10 -1

-15 -1.5 0 100 200 300 400

0 100 200 300 400 Time (ms)
Time (ms)

The element connected between a and b could be

(A)

a b

(B)

a b

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(C)

a b

(D)

a b

4. The two inputs of a CRO are fed with two stationary periodic signals. In the X-Y mode, the screen shows a
figure which changes from ellipse to circle and back to ellipse with its major axis changing orientation
slowly and repeatedly. The following inference can be made from this.
(A) The signals are not sinusoidal
(B) The amplitudes of the signals are very close but not equal
(C) The signals are sinusoidal with their frequencies very close but not equal
(D) There is a constant but small phase difference between the signals

5. The increasing order of speed of data access for the following devices is
(i) Cache Memory (ii) CDROM (iii) Dynamic RAM (iv) Processor Registers
(v) Magnetic Tape
(A) ( v) ( ii) ( iii) (iv ) (i ) (C) ( ii) (i ) ( iii) ( iv) ( v)
(B) (v ) (ii ) (iii ) (i ) (iv ) (D) (v ) ( ii) (i ) ( iii) (iv )

6. A field excitation of 20 A in a certain alternator results in an armature current of 400A in short circuit and
a terminal voltage of 2000V on open circuit. The magnitude of the internal voltage drop within the
machine at a load current of 200A is
(A) 1 V (C) 100 V
(B) 10 V (D) 1000 V

7. The current through the 2 kΩ resistance in the circuit shown is

(A) 0m A (C) 2m A
(B) 1m A (D) 6m A
1KΩ C 1KΩ

A 2KΩ B

1KΩ D 1KΩ

6V

8. Out of the following plant categories

(i) Nuclear (ii) Run-of-river (iii) Pump Storage (iv) Diesel
The base load power plants are
(A) (i) and (ii) (C) (i), (ii) and (iv)
(B) (ii) and (iii) (D) (i), (iii) & (iv)

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9. For a fixed value of complex power flow in a transmission line having a sending end voltage V, the real
power loss will be proportional to
(A) V (C) 1/V2
(B) V2 (D) 1/V

10. How many 200W/220V incandescent lamps connected in series would consume the same total power as a
single 100W/220V incandescent lamp?
(A) not possible (C) 3
(B) 4 (D) 2

11. A Linear Time Invariant system with an impulse response h(t) produces output y(t) when input x(t)
is applied. When the input x (t- ) is applied to a system with impulse response h (t- ), the output will
be
(A) y(t) (C) y(t- )
(B) y(2(t- )) (D) y(t-2

12. The nature of feedback in the opamp circuit shown is

(A) Current - Current feedback (C) Current - Voltage feedback
(B) Voltage - Voltage feedback (D) Voltage - Current feedback

+6V
1KΩ 2KΩ
-
+ Vout

- 6V
Vin

13. The complete set of only those Logic Gates designated as Universal Gates is
(A) NOT, OR and AND Gates (C) NOR and NAND Gates
(B) XNOR, NOR and NAND Gate (D) XOR, NOR and NAND Gates

14. The single phase, 50Hz, iron core transformer in the circuit has both the vertical arms of cross sectional
area 20cm2 and both the horizontal arms of cross sectional area 10cm2. If the two windings shown
were wound instead on opposite horizontal arms, the mutual inductance will

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(A) double (C) be halved

(B) remain same (D) become one quarter

15. A 3-phase squirrel cage induction motor supplied from a balanced 3-phase source drives a mechanical load.
The torque-speed characteristics of the motor (solid curve) and of the load (dotted curve) are shown. Of the
two equilibrium points A and B, which of the following options correctly describes the stability of A and
B?
(A) A is stable B is unstable (C) Both are stable
(B) A is unstable B is stable (D) Both are unstable

B
Torque

0 1.0 N/N sync

16. An SCR is considered to be a semi-controlled device because

(A) it can be turned OFF but not ON with a gate pulse
(B) it conducts only during one half-cycle of an alternating current wave
(C) it can be turned ON but not OFF with a gate pulse
(D) it can be turned ON only during one half-cycle of an alternating voltage wave

17. The polar plot of an open loop stable system is shown below. The closed loop system is
(A) Always stable
(B) Marginally stable
(C) Unstable with one pole on the RH s-plane
(D) Unstable with two poles on the RH s-plane

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Imaginary

ω=∞
-1.42 Real

ω=0

18. The first two rows of Routh's tabulation of a third order equation are as follows.

s3 2 2

s3 4 4.

This means there are

(A) two roots at s= ± j and one root in right half s-plane

(B) two roots at s = ±j2 and one root in left half s-plane
(C) two roots at s = ± j2 and one root in right half s-plane
(D) two roots at s = ±j and one root in left half s-plane

19. The asymptotic approximation of the log-magnitude vs frequency plot of a system containing only
real poles and zeros is shown. Its transfer function is
(A) (C)

(B)
(D)

-40 dB / dec
-60 dB / dec
80 dB

ω rad / s
0.1 2 5 25

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20. The trace and determinant of a 2 2 matrix are known to be -2 and -35 respectively. Its eigen
values are
(A) -30 and -5 (C) -7 and 5
(B) -35 and -1 (D) 17.5 and -2

Q. No. 21 – 56 Carry Two Marks Each

21. The following circuit has R = 10kΩ , C = 10μ F . The input voltage is a sinusoid at 50Hz with an rms
value of 10V. Under ideal conditions, the current i s from the source is
(A) 10 π mA leading by 900 (C) 10 mA leading by 900
(B) 20 π mA leading by 900 (D) 10 π mA lagging by 900

10kΩ

iS +
OPAMP
Vs = 10V rms, -
50HZ
10kΩ

R
C
10μF

22. In the figure shown, all elements used are ideal. For time t<0, S 1 remained closed and S 2 open. At
t=0, S 1 is opened and S 2 is closed. If the voltage V c2 across the capacitor C 2 at t=0 is zero, the
voltage across the capacitor combination at t=0+ will be
(A) 1V (C) 1.5 V
(B) 2 V (D) 3 V

S1 S2

3V
C1 C2
1F 2F

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23. Transformer and emitter follower can both be used for impedance matching at the output of an audio
amplifier. The basic relationship between the input power P in and output power P out in both the cases is
(A) P in = P out for both transformer and emitter follower
(B) P in > P out for both transformer and emitter follower
(C) P in < P out for transformer and P in = P out for emitter follower
(D) P in = P out for transformer and P in < P out for emitter follower

24. The equivalent capacitance of the input loop of the circuit shown is
(A) 2μ F (C) 200μ F
(B) 100μ F (D) 4μF

I1 1kΩ 1kΩ

1kΩ
input
loop 49I1 100μF
100μF

25. In an 8085 microprocessor, the contents of the Accumulator, after the following instructions are executed
will become
XRA A
MVIB F0H
SUB B
(A) 01 H (C) F0 H
(B) 0F H (D) 10 H

26. For the Y-bus matrix of a 4-bus system given in per unit, the buses having shunt elements are

(A) 3 and 4 (C) 1 and 2

(B) 2 and 3 (D) 1,2 and 4

27. The unit-step response of a unity feedback system with open loop transfer function G(s) =
is shown in the figure. The value of K is
(A) 0.5 (C) 4
(B) 2 (D) 6

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0.75
response
0.5

0.25

0
0 1 2 3 4
time(s)

28. The open loop transfer function of a unity feedback system is given by G(s) = The gain

margin of this system is

(A) 11.95dB (C) 21.33dB
(B) 17.67dB (D) 23.9dB

29. Match the items in List-I with the items in List-II and select the correct answer using the codes given
below the lists.

List I List II
To Use
a. improve power factor 1. shunt reactor
b. reduce the current ripples 2. shunt capacitor
c. increase the power flow in line 3. series capacitor
d. reduce the Ferranti effect 4. series reactor
(A) a → 2 b→3 c →4 d →1 (C) a → 4 b→3 c →1 d →2
(B) a → 2 b→4 c →3 d →1 (D) a → 4 b→1 c →3d →2

30. Match the items in List-I with the items in List-II and select the correct answer using the codes given.

List I List II
Type of transmission line Type of distance relay preferred
a. Short Line 1. Ohm Relay
b. Medium Line 2. Reactance Relay
c. Long Line 3. Mho Relay

Codes :
A B C
(A) 2 1 3
(B) 3 2 1
(C) 1 2 3
(D) 1 3 2
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31. Three generators are feeding a load of 100MW. The details of the generators are

Rating(MW) Efficiency (%) Regulation (p .u) on 100 MVA base

Generator-1 100 20 0.02
Generator-2 100 30 0.04
Generator-3 100 40 0.03

In the event of increased load power demand, which of the following will happen?

(A) All the generators will share equal power

(B) Generator-3 will share more power compared to Generator-1
(C) Generator-1 will share more power compared to Generator-2
(D) Generator-2 will share more power compared to Generator-3

32. A 500 MW, 21kV, 50 Hz, 3-phase, 2- pole synchronous generator having a rated p.f = 0.9 has a moment of
inertia of 27.5×103 kg-m2. The inertia constant (H) will be
(A) 2.44 s (C) 4.88 s
(B) 2.71 s (D) 5.42 s

33. f(x ,y) is a continuous function defined over (x ,y) ∈ [0,1] × [ 0,1]. Given the two constraints, x > y2 and y >
x2, the volume under f(x ,y) is
(A) (C)

(B) (D)

34. Assume for simplicity that N people, all born in April (a month of 30 days), are collected in a room.
Consider the event of at least two people in the room being born on the same date of the month, even
if in different years, e.g. 1980 and 1985. What is the smallest N so that the probability of this event
exceeds 0.5?
(A) 20 (C) 15
(B) 7 (D) 16

35. A cascade of 3 Linear Time Invariant systems is causal and unstable. From this, we conclude that
(A) each system in the cascade is individually causal and unstable
(B) at least one system is unstable and at least one system is causal
(C) at least one system is causal and all systems are unstable
(D) the majority are unstable and the majority are causal

36. The Fourier Series coefficients, of a periodic signal x(t), expressed as x(t) = are given by

a -2 = - j1; a -1 = 0.5 + j0.2; a 0 = j2; a 1 = 0.5 – j0.2; a 2 = 2 + j1; and a k = 0; for > 2.
Which of the following is true?
(A) x(t) has finite energy because only finitely many coefficients are non-zero
(B) x(t) has zero average value because it is periodic
(C) The imaginary part of x(t) is constant
(D) The real part of x(t) is even

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37. The z-transform of a signal x[n] is given by 4z-3 + 3z-1 + 2 – 6z2 + 2z3. It is applied to a system, with a
transfer function H(z) = 3z-1 -2. Let the output be y(n).Which of the following is true?
(A) y(n) is non causal with finite support
(B) y(n) is causal with infinite support
(C) y(n) = 0;|n|>3

(D)

38. A cubic polynomial with real coefficients

(A) can possibly have no extrema and no zero crossings
(B) may have up to three extrema and upto 2 zero crossings
(C) cannot have more than two extrema and more than three zero crossings
(D) will always have an equal number of extrema and zero crossings

39. Let x2 -117 = 0. The iterative steps for the solution using Newton-Raphson's
method is given by
(A) (C)

(B) (D)

40. F(x ,y) = . It’s line integral over the straight line from (x, y) = ( 0,2) to (x,
y) = (2, 0) evaluates to
(A) - 8 (C) 8
(B) 4 (D) 0

41. An ideal opamp circuit and its input waveform are shown in the figures. The output waveform of
this circuit will be

2 1kΩ 6V
Vin +
1 Vout
-
2kΩ
V 0
t4 t5 t6 -3V
t1 t2 t3
-1 1kΩ

-2

-3

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(A)
6

0 t3 t6
t

-3

(B)

0 t3 t6
t
-3

(C)
6

t6
0
t2 t4 t
-3

(D)

V
0 t2 t4 t5
-3 t

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42. A 220V, 50Hz, single-phase induction motor has the following connection diagram and winding
orientations shown. MM' is the axis of the main stator winding (M 1 M 2 ) and AA' is that of the auxiliary
winding (A 1 A 2 ). Directions of the winding axes indicate direction of flux when currents in the
windings are in the directions shown. Parameters of each winding are indicated. When switch S is
closed, the motor
(A) rotates clockwise (C) does not rotate
(B) rotates anticlockwise (D) rotates momentarily and comes to a halt

M1
rm = 0.1Ω
ra = 1Ω Lm=0.1/πH
La = 10/πH M2

A1 A2
S A A’

220V Rotor
50HZ

M’

43. The circuit shows an ideal diode connected to a pure inductor and is connected to a purely sinusoidal 50Hz
voltage source. Under ideal conditions the current waveform through the inductor will look like
D

+ -
+ L = (0.1/π)H
Vs = 10 sin 100 πt

(A)
1.5
current

0.5

0
0 10 20 30 40 50
time(ms)

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(B)
1.5
current
1

0.5

0
0 10 20 30 40
time (ms)

(C)

1.5
current

0.5

0 10 20 30 40 50
(D) time(ms)

1.5
current

0.5

0
0 10 20 30 40 50
times(ms)

44. The Current Source Inverter shown in figure, is operated by alternately turning on thyristor pairs
(T 1 , T 2 ) and (T 3 , T 4 ). If the load is purely resistive, the theoretical maximum output frequency
obtainable will be
(A) 125kHz (C) 500kHz
(B) 250kHz (D) 50kHz

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T1 T3
0.1 μF

- +
D1 D3
10Ω 10A

D4 D2

- +
T4 0.1 μF T2

45. In the chopper circuit shown, the main thyristor (T M ) is operated at a duty ratio of 0.8, which is much larger
the commutation interval. If the maximum allowable reapplied dv/dt on TM is 50 Vμ/s, what should be the
theoretical minimum value of C 1 ? Assume current ripple through L 0 to be negligible
(A) 0.2 μ F (C) 2 μ F
(B) 0.02 μ F (D) 20μ F

+
TM
L1

C1 TA L0
- +

C0 8Ω
D1 D0

46. Match the switch arrangements on the top row to the steady-state V-I characteristics on the lower
row. The steady state operating points are shown by large black dots.

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(A) (B) (C) (D)

+ - + -
+ -
+ -

is is is is
(I) (II) (III) (IV)

Vs Vs Vs Vs

Codes :

A B C D

(A) I II III IV
(B) II IV I III
(C) IV III I II
(D) IV III II I

47. For the circuit shown, find out the current flowing through the 2 Ω resistance. Also identify the changes to
be made to double the current through the 2Ω resistance
(A) (5A ; Put V S = 20V) (C) (5A ; Put V S = 10V)
(B) (2A ; Put V S = 8V) (D) (7A ; Put V S = 12V)

Vs = 4V Is = 5A
+
- 2Ω

48. The figure shows a three-phase delta connected load supplied from a 400V, 50 Hz, 3-phase
balanced source. The pressure coil (PC) and current coil (CC) of a wattmeter are connected to the
load as shown, with the coil polarities suitably selected to ensure a positive deflection. The wattmeter
reading will be
(A) 0 (C) 800 Watt
(B) 1600 Watt (D) 400 Watt
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a
Z1 = (100 + j0)Ω Z2 = (100 + j0) Ω
Z2
3-phas
Balanced
Z1
supply
CC
400 Volts
50 Hz.
C
b PC

49. An average-reading digital multimeter reads 10V when fed with a triangular wave, symmetric about
the time-axis. For the same input an rms-reading meter will read.
(A)

(B)

(C)
(D) 10

50. Figure shows the extended view of a 2 pole dc machine with 10 armature conductors. Normal
brush positions are shown by A and B, placed at the interpolar axis. If the brushes are now shifted, in
the direction of rotation, to A' and B' as shown, the voltage waveform V A’ B’ will resemble

N
S

B’ A
B - A +
- +

1 2 3 4 5 1’ 2’ 3’ 4’ 5’
rotation at speed ω rad/sec

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(A) (B)

VA’B’
VA’B’

ωt ωt
0 0.2π 0.4π 0.6π 0.8π π 0 0.2π 0.4π 0.6π 0.8π π

(C) (D)

VA’B’ VA’B’

ωt
ωt
0 0.2π 0.4π 0.6π 0.8π π
0 0.2π 0.4π 0.6π 0.8π π

Common Date Question

Common Data for Question 51 and 52:

a
A

B b

C c

N S1 S2

The star-delta transformer shown above is excited on the star side with a balanced, 4-wire, 3-
phase, sinusoidal voltage supply of rated magnitude. The transformer is under no load
condition.

51. With both S1 and S2 open, the core flux waveform will be
(A) a sinusoid at fundamental frequency
(B) flat- topped with third harmonic
(C) peaky with third- harmonic
(D) none of these

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52. With S2 closed and S1 open, the current waveform in the delta winding will be
(A) a sinusoid at fundamental frequency (C) only third harmonic
(B) flat- topped with third harmonic (D) none of these

Common Data Questions: 53 & 54

The circuit diagram shows a two winding, lossless transformer with no leakage flux, excited from a
current source, i(t), whose waveform is also shown. The transformer has a magnetizing inductance of
(400/π) mH.

i(t)
1:1
A
S 10A

i(t) 30Ω
0
5ms 10ms 15ms 20ms 25ms 30ms

10A t

53. The peak voltage across A and B, with S open is

(A) 400/πV (C) 4000/πV
(B) 800V (D) 800/πV
54. If the waveform of i(t) is changed to i(t)=10sin(100 πt) A, the peak voltage across A and B with S
closed is
(A) 400V (C) 320V
(B) 240V (D) 160V

Common Data Questions: 55 & 56

A system is described by the following state and output equations

y(t) = x 1 (t)

where u(t) is the input and y(t) is the output

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55. The system transfer function is

(A) (D)
(B)

(C)

56. The state-transition matrix of the above system is

(A) (C)

(B) (D)

Linked Answer Questions

Statement for Linked Answer Questions: 57 & 58

A C

Coil 1 Coil 2

B D

The figure above shows coils 1 and 2, with dot markings as shown, having 4000 and 6000 turns
respectively. Both the coils have a rated current of 25A. Coil 1 is excited with single phase, 400V, 50Hz
supply

57. The coils are to be connected to obtain a single phase, 400/1000V, auto- transformer to drive a
load of 10kVA. Which of the options given should be exercised to realize the required auto-transformer?
(A) Connect A and D; Common B (C) Connect A and C; Common B
(B) Connect B and D; Common C (D) Connect A and C; Common D

58. In the autotransformer obtained in Question 57, the current in each coil is
(A) Coil-1 is 25 A and Coil-2 is 10 A (C) Coil-1 is 10 A and Coil-2 is 15 A
(B) Coil-1 is 10 A and Coil-2 is 25 A (D) Coil-1 is 15 A and Coil-2 is 10 A

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Statement for Linked Answer Questions 59 & 60:

2kΩ 3VAB
+ - A

5V + 2kΩ 1kΩ
-

59. For the circuit given above, the Thevenin’s resistance across the terminals A and B is
(A) 0.5kΩ (C) 1kΩ
(B) 0.2kΩ (D) 0.11kΩ

60. For the circuit given above, the Thevenin’s voltage across the terminals A and B is
(A) 1.25V (C) 1V
(B) 0.25V (D) 0.5V

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