Page 1
GATE EE  2001
SECTION  A
1. This question consists of TWENTYFIVE subquestions (1.1 – 1.25) of ONE mark
each. For each of these subquestions, four possible alternatives (A, B, C and D)
are given, out of which ONLY ONE is correct. Indicate the correct answer by
darkening the appropriate bubble against the question number on the left hand
side of the Objective Response Sheet (ORS). You may use the answer book
provided for any rough work, if needed.
1.1 In a series RLC circuit at resonance, the magnitude of the voltage developed
across the capacitor
(a) is always zero
(b) can never be greater than the input voltage
(c) can be greater than the input voltage, however, it is 90° out of phase with
the input voltage
(d) can be greater than the input voltage, and is in phase with the input voltage.
1.2 Two incandescent light bulbs of 40 W and 60 W rating are connected in series
across the mains. Then
(a) the bulbs together consume 100 W
(b) the bulbs together consume 50W
(c) the 60 W bulb glows brighter
(d) the 40 W bulb glows brighter
1.3 A unit step voltage is applied at t = 0 to a series RL circuit with zero initial
conditions.
(a) It is possible for the current to be oscillatory.
(b) The voltage across the resistor at t = 0
+
is zero.
(c) The energy stored in the inductor in the steady state is zero.
(d) The resistor current eventually falls to zero.
1.4 Given two coupled inductors L
1
and L
2
, their mutual inductance M satisfies
(a)
2 2
1 2
M L L = + (b)
( )
1 2
2
L L
M
+
>
(c) M >
1 2
L L (d)
1 2
M L L =
1.5 A passive 2port network is in a steadystate. Compared to its input, the steady
state output can never offer
(a) higher voltage (b) lower impedance
(c) greater power (d) better regulation
Page 2
GATE EE  2001
SECTION  A
1. This question consists of TWENTYFIVE subquestions (1.1 – 1.25) of ONE mark
each. For each of these subquestions, four possible alternatives (A, B, C and D)
are given, out of which ONLY ONE is correct. Indicate the correct answer by
darkening the appropriate bubble against the question number on the left hand
side of the Objective Response Sheet (ORS). You may use the answer book
provided for any rough work, if needed.
1.1 In a series RLC circuit at resonance, the magnitude of the voltage developed
across the capacitor
(a) is always zero
(b) can never be greater than the input voltage
(c) can be greater than the input voltage, however, it is 90° out of phase with
the input voltage
(d) can be greater than the input voltage, and is in phase with the input voltage.
1.2 Two incandescent light bulbs of 40 W and 60 W rating are connected in series
across the mains. Then
(a) the bulbs together consume 100 W
(b) the bulbs together consume 50W
(c) the 60 W bulb glows brighter
(d) the 40 W bulb glows brighter
1.3 A unit step voltage is applied at t = 0 to a series RL circuit with zero initial
conditions.
(a) It is possible for the current to be oscillatory.
(b) The voltage across the resistor at t = 0
+
is zero.
(c) The energy stored in the inductor in the steady state is zero.
(d) The resistor current eventually falls to zero.
1.4 Given two coupled inductors L
1
and L
2
, their mutual inductance M satisfies
(a)
2 2
1 2
M L L = + (b)
( )
1 2
2
L L
M
+
>
(c) M >
1 2
L L (d)
1 2
M L L =
1.5 A passive 2port network is in a steadystate. Compared to its input, the steady
state output can never offer
(a) higher voltage (b) lower impedance
(c) greater power (d) better regulation
GATE EE  2001
1.6 A singlephase transformer is to be switched to the supply to have minimum
inrush current. The switch should be closed at
(a) maximum supply voltage (b) zero supply voltage
(c)
1
2
maximum supply voltage (d)
1
2
maximum supply voltage
1.7 It is desirable to eliminate 5
th
harmonic voltage from the phase voltage of an
alternator. The coils should be shortpitched by an electrical angle of
(a) 30° (b) 36° (c) 72° (d) 18°
1.8 Fig.P1.8 shows the magnetization curves of an alternator at rated armature
current, unity power factor and also at no load. The magnetization curve for rated
armature current, 0.8 power factor leading is given by
(a) curve A (b) curve B (c) curve C (d) curve D
1.9 The core flux of a practical transformer with a resistive load
(a) is strictly constant with load changes
(b) increases linearly with load
(c) increases as the square root of the load
(d) decreases with increased load
1.10 , and
d d d
X X X ' '' are steady state daxis synchronous reactance, transient daxis
reactance and subtransient daxis reactance of a synchronous machine
respectively. Which of the following statements is true?
(a) >
d d d
X X X ' '' > (b) >
d d d
X X X '' ' >
(c)
d d d
X X X ' '' > > (d)
d d d
X X X '' ' > >
1.11 A 50 Hz balanced threephase, Yconnected supply is connected to a balanced
three phase Yconnected load. If the instantaneous phasea of the supply voltage
is Vcos(?t) and the phasea of the load current is Icos(?tf), the instantaneous
threephase power is
(a) a constant with a magnitude of VIcosf
A
B
C
D
No load
Rated armature
current unit pf
Exciting current
Page 3
GATE EE  2001
SECTION  A
1. This question consists of TWENTYFIVE subquestions (1.1 – 1.25) of ONE mark
each. For each of these subquestions, four possible alternatives (A, B, C and D)
are given, out of which ONLY ONE is correct. Indicate the correct answer by
darkening the appropriate bubble against the question number on the left hand
side of the Objective Response Sheet (ORS). You may use the answer book
provided for any rough work, if needed.
1.1 In a series RLC circuit at resonance, the magnitude of the voltage developed
across the capacitor
(a) is always zero
(b) can never be greater than the input voltage
(c) can be greater than the input voltage, however, it is 90° out of phase with
the input voltage
(d) can be greater than the input voltage, and is in phase with the input voltage.
1.2 Two incandescent light bulbs of 40 W and 60 W rating are connected in series
across the mains. Then
(a) the bulbs together consume 100 W
(b) the bulbs together consume 50W
(c) the 60 W bulb glows brighter
(d) the 40 W bulb glows brighter
1.3 A unit step voltage is applied at t = 0 to a series RL circuit with zero initial
conditions.
(a) It is possible for the current to be oscillatory.
(b) The voltage across the resistor at t = 0
+
is zero.
(c) The energy stored in the inductor in the steady state is zero.
(d) The resistor current eventually falls to zero.
1.4 Given two coupled inductors L
1
and L
2
, their mutual inductance M satisfies
(a)
2 2
1 2
M L L = + (b)
( )
1 2
2
L L
M
+
>
(c) M >
1 2
L L (d)
1 2
M L L =
1.5 A passive 2port network is in a steadystate. Compared to its input, the steady
state output can never offer
(a) higher voltage (b) lower impedance
(c) greater power (d) better regulation
GATE EE  2001
1.6 A singlephase transformer is to be switched to the supply to have minimum
inrush current. The switch should be closed at
(a) maximum supply voltage (b) zero supply voltage
(c)
1
2
maximum supply voltage (d)
1
2
maximum supply voltage
1.7 It is desirable to eliminate 5
th
harmonic voltage from the phase voltage of an
alternator. The coils should be shortpitched by an electrical angle of
(a) 30° (b) 36° (c) 72° (d) 18°
1.8 Fig.P1.8 shows the magnetization curves of an alternator at rated armature
current, unity power factor and also at no load. The magnetization curve for rated
armature current, 0.8 power factor leading is given by
(a) curve A (b) curve B (c) curve C (d) curve D
1.9 The core flux of a practical transformer with a resistive load
(a) is strictly constant with load changes
(b) increases linearly with load
(c) increases as the square root of the load
(d) decreases with increased load
1.10 , and
d d d
X X X ' '' are steady state daxis synchronous reactance, transient daxis
reactance and subtransient daxis reactance of a synchronous machine
respectively. Which of the following statements is true?
(a) >
d d d
X X X ' '' > (b) >
d d d
X X X '' ' >
(c)
d d d
X X X ' '' > > (d)
d d d
X X X '' ' > >
1.11 A 50 Hz balanced threephase, Yconnected supply is connected to a balanced
three phase Yconnected load. If the instantaneous phasea of the supply voltage
is Vcos(?t) and the phasea of the load current is Icos(?tf), the instantaneous
threephase power is
(a) a constant with a magnitude of VIcosf
A
B
C
D
No load
Rated armature
current unit pf
Exciting current
GATE EE  2001
(b) a constant with a magnitude of (3/2)VIcosf
(c) timevarying with an average value of (3/2) VIcosf and a frequency of 100
Hz.
(d) timevarying with an average value of VIcosf and a frequency of 50 Hz.
1.12 In the protection of transformers, harmonic restraint is used to guard aainst
(a) magnetizing inrush current (b) unbalanced operation
(c) lightning (d) switching overvoltages
1.13 A lossless radial transmission line with surge impedance loading
(a) takes negative VAR at sending end and zero VAR at receiving end
(b) takes positive VAR at sending end and zero VAR at receiving end
(c) has flat voltage profile and unity power factor at all points along it
(d) has sending end voltage higher than receiving end voltage and unity power
factor at sending end
1.14 The polar plot of a type1, 3pole, openloop system is shown in Fig.P1.14. the
closed loop system is
(a) always stable
(b) marginally stable
(c) unstable with one pole on the right half splane
(d) unstable with two poles on the right half splane
1.15 Given the homogeneous statespace equaion
3 1
0 2
x x
 ? ?
=
? ?

? ?
&
the steady state value ( ) lim ,
ss
t
x x t
?8
= given the initial state value of x(0) = [10 –
10]
T
, is
(a)
0
0
ss
x
? ?
=
? ?
? ?
(b)
3
2
ss
x
 ? ?
=
? ?

? ?
(c)
10
10
ss
x
 ? ?
=
? ?
? ?
(d)
ss
x
8 ? ?
=
? ?
8
? ?
GH  plane
1.42
0
o
w=8
w=0
Page 4
GATE EE  2001
SECTION  A
1. This question consists of TWENTYFIVE subquestions (1.1 – 1.25) of ONE mark
each. For each of these subquestions, four possible alternatives (A, B, C and D)
are given, out of which ONLY ONE is correct. Indicate the correct answer by
darkening the appropriate bubble against the question number on the left hand
side of the Objective Response Sheet (ORS). You may use the answer book
provided for any rough work, if needed.
1.1 In a series RLC circuit at resonance, the magnitude of the voltage developed
across the capacitor
(a) is always zero
(b) can never be greater than the input voltage
(c) can be greater than the input voltage, however, it is 90° out of phase with
the input voltage
(d) can be greater than the input voltage, and is in phase with the input voltage.
1.2 Two incandescent light bulbs of 40 W and 60 W rating are connected in series
across the mains. Then
(a) the bulbs together consume 100 W
(b) the bulbs together consume 50W
(c) the 60 W bulb glows brighter
(d) the 40 W bulb glows brighter
1.3 A unit step voltage is applied at t = 0 to a series RL circuit with zero initial
conditions.
(a) It is possible for the current to be oscillatory.
(b) The voltage across the resistor at t = 0
+
is zero.
(c) The energy stored in the inductor in the steady state is zero.
(d) The resistor current eventually falls to zero.
1.4 Given two coupled inductors L
1
and L
2
, their mutual inductance M satisfies
(a)
2 2
1 2
M L L = + (b)
( )
1 2
2
L L
M
+
>
(c) M >
1 2
L L (d)
1 2
M L L =
1.5 A passive 2port network is in a steadystate. Compared to its input, the steady
state output can never offer
(a) higher voltage (b) lower impedance
(c) greater power (d) better regulation
GATE EE  2001
1.6 A singlephase transformer is to be switched to the supply to have minimum
inrush current. The switch should be closed at
(a) maximum supply voltage (b) zero supply voltage
(c)
1
2
maximum supply voltage (d)
1
2
maximum supply voltage
1.7 It is desirable to eliminate 5
th
harmonic voltage from the phase voltage of an
alternator. The coils should be shortpitched by an electrical angle of
(a) 30° (b) 36° (c) 72° (d) 18°
1.8 Fig.P1.8 shows the magnetization curves of an alternator at rated armature
current, unity power factor and also at no load. The magnetization curve for rated
armature current, 0.8 power factor leading is given by
(a) curve A (b) curve B (c) curve C (d) curve D
1.9 The core flux of a practical transformer with a resistive load
(a) is strictly constant with load changes
(b) increases linearly with load
(c) increases as the square root of the load
(d) decreases with increased load
1.10 , and
d d d
X X X ' '' are steady state daxis synchronous reactance, transient daxis
reactance and subtransient daxis reactance of a synchronous machine
respectively. Which of the following statements is true?
(a) >
d d d
X X X ' '' > (b) >
d d d
X X X '' ' >
(c)
d d d
X X X ' '' > > (d)
d d d
X X X '' ' > >
1.11 A 50 Hz balanced threephase, Yconnected supply is connected to a balanced
three phase Yconnected load. If the instantaneous phasea of the supply voltage
is Vcos(?t) and the phasea of the load current is Icos(?tf), the instantaneous
threephase power is
(a) a constant with a magnitude of VIcosf
A
B
C
D
No load
Rated armature
current unit pf
Exciting current
GATE EE  2001
(b) a constant with a magnitude of (3/2)VIcosf
(c) timevarying with an average value of (3/2) VIcosf and a frequency of 100
Hz.
(d) timevarying with an average value of VIcosf and a frequency of 50 Hz.
1.12 In the protection of transformers, harmonic restraint is used to guard aainst
(a) magnetizing inrush current (b) unbalanced operation
(c) lightning (d) switching overvoltages
1.13 A lossless radial transmission line with surge impedance loading
(a) takes negative VAR at sending end and zero VAR at receiving end
(b) takes positive VAR at sending end and zero VAR at receiving end
(c) has flat voltage profile and unity power factor at all points along it
(d) has sending end voltage higher than receiving end voltage and unity power
factor at sending end
1.14 The polar plot of a type1, 3pole, openloop system is shown in Fig.P1.14. the
closed loop system is
(a) always stable
(b) marginally stable
(c) unstable with one pole on the right half splane
(d) unstable with two poles on the right half splane
1.15 Given the homogeneous statespace equaion
3 1
0 2
x x
 ? ?
=
? ?

? ?
&
the steady state value ( ) lim ,
ss
t
x x t
?8
= given the initial state value of x(0) = [10 –
10]
T
, is
(a)
0
0
ss
x
? ?
=
? ?
? ?
(b)
3
2
ss
x
 ? ?
=
? ?

? ?
(c)
10
10
ss
x
 ? ?
=
? ?
? ?
(d)
ss
x
8 ? ?
=
? ?
8
? ?
GH  plane
1.42
0
o
w=8
w=0
GATE EE  2001
1.16 If an energy meter disc makes 10 revolutions in 100 seconds when a load of 450
W is connected to it, the meter constant (in rev/kWh) is
(a) 1000 (b) 500 (c) 1600 (d) 800
1.17 The minimum number of wattmeter (s) required to measure 3phase, 3wire
balanced or unbalanced power is
(a) 1 (b) 2 (c) 3 (d) 4
1.18 In the singlestage transistor amplifier circuit shown in Fig.P1.18, the capacitor C
E
is removed. Then, the ac smallsignal midband voltage gain of the amplifier
(a) increases (b) decreases
(c) is unaffected (d) drops to zero
1.19. Among the following four, the slowest ADC (analogtodigital converter) is
(a) parallel comparator (i.e., flash) type
(b) successive approximation type
(c) integrating type (d) counting type
1.20. The output of a logic gate is “1” when all its inputs are at logic “0”. The gate is
either
(a) a NAND or an EXOR gate (b) a NOR or an EXOR gate
(c) an AND or an EXNOR gate (d) a NOR or an EXNOR gate
1.21. The output f of the 4to1 MUX shown in Fig.P1.21 is
(a) xy x + (b) x+y (c) x y + (d) xy+x
C E
+12V
Input
Output
+

+
V CC
2
1
0
S 1 S 0
X
Y
MUX
Page 5
GATE EE  2001
SECTION  A
1. This question consists of TWENTYFIVE subquestions (1.1 – 1.25) of ONE mark
each. For each of these subquestions, four possible alternatives (A, B, C and D)
are given, out of which ONLY ONE is correct. Indicate the correct answer by
darkening the appropriate bubble against the question number on the left hand
side of the Objective Response Sheet (ORS). You may use the answer book
provided for any rough work, if needed.
1.1 In a series RLC circuit at resonance, the magnitude of the voltage developed
across the capacitor
(a) is always zero
(b) can never be greater than the input voltage
(c) can be greater than the input voltage, however, it is 90° out of phase with
the input voltage
(d) can be greater than the input voltage, and is in phase with the input voltage.
1.2 Two incandescent light bulbs of 40 W and 60 W rating are connected in series
across the mains. Then
(a) the bulbs together consume 100 W
(b) the bulbs together consume 50W
(c) the 60 W bulb glows brighter
(d) the 40 W bulb glows brighter
1.3 A unit step voltage is applied at t = 0 to a series RL circuit with zero initial
conditions.
(a) It is possible for the current to be oscillatory.
(b) The voltage across the resistor at t = 0
+
is zero.
(c) The energy stored in the inductor in the steady state is zero.
(d) The resistor current eventually falls to zero.
1.4 Given two coupled inductors L
1
and L
2
, their mutual inductance M satisfies
(a)
2 2
1 2
M L L = + (b)
( )
1 2
2
L L
M
+
>
(c) M >
1 2
L L (d)
1 2
M L L =
1.5 A passive 2port network is in a steadystate. Compared to its input, the steady
state output can never offer
(a) higher voltage (b) lower impedance
(c) greater power (d) better regulation
GATE EE  2001
1.6 A singlephase transformer is to be switched to the supply to have minimum
inrush current. The switch should be closed at
(a) maximum supply voltage (b) zero supply voltage
(c)
1
2
maximum supply voltage (d)
1
2
maximum supply voltage
1.7 It is desirable to eliminate 5
th
harmonic voltage from the phase voltage of an
alternator. The coils should be shortpitched by an electrical angle of
(a) 30° (b) 36° (c) 72° (d) 18°
1.8 Fig.P1.8 shows the magnetization curves of an alternator at rated armature
current, unity power factor and also at no load. The magnetization curve for rated
armature current, 0.8 power factor leading is given by
(a) curve A (b) curve B (c) curve C (d) curve D
1.9 The core flux of a practical transformer with a resistive load
(a) is strictly constant with load changes
(b) increases linearly with load
(c) increases as the square root of the load
(d) decreases with increased load
1.10 , and
d d d
X X X ' '' are steady state daxis synchronous reactance, transient daxis
reactance and subtransient daxis reactance of a synchronous machine
respectively. Which of the following statements is true?
(a) >
d d d
X X X ' '' > (b) >
d d d
X X X '' ' >
(c)
d d d
X X X ' '' > > (d)
d d d
X X X '' ' > >
1.11 A 50 Hz balanced threephase, Yconnected supply is connected to a balanced
three phase Yconnected load. If the instantaneous phasea of the supply voltage
is Vcos(?t) and the phasea of the load current is Icos(?tf), the instantaneous
threephase power is
(a) a constant with a magnitude of VIcosf
A
B
C
D
No load
Rated armature
current unit pf
Exciting current
GATE EE  2001
(b) a constant with a magnitude of (3/2)VIcosf
(c) timevarying with an average value of (3/2) VIcosf and a frequency of 100
Hz.
(d) timevarying with an average value of VIcosf and a frequency of 50 Hz.
1.12 In the protection of transformers, harmonic restraint is used to guard aainst
(a) magnetizing inrush current (b) unbalanced operation
(c) lightning (d) switching overvoltages
1.13 A lossless radial transmission line with surge impedance loading
(a) takes negative VAR at sending end and zero VAR at receiving end
(b) takes positive VAR at sending end and zero VAR at receiving end
(c) has flat voltage profile and unity power factor at all points along it
(d) has sending end voltage higher than receiving end voltage and unity power
factor at sending end
1.14 The polar plot of a type1, 3pole, openloop system is shown in Fig.P1.14. the
closed loop system is
(a) always stable
(b) marginally stable
(c) unstable with one pole on the right half splane
(d) unstable with two poles on the right half splane
1.15 Given the homogeneous statespace equaion
3 1
0 2
x x
 ? ?
=
? ?

? ?
&
the steady state value ( ) lim ,
ss
t
x x t
?8
= given the initial state value of x(0) = [10 –
10]
T
, is
(a)
0
0
ss
x
? ?
=
? ?
? ?
(b)
3
2
ss
x
 ? ?
=
? ?

? ?
(c)
10
10
ss
x
 ? ?
=
? ?
? ?
(d)
ss
x
8 ? ?
=
? ?
8
? ?
GH  plane
1.42
0
o
w=8
w=0
GATE EE  2001
1.16 If an energy meter disc makes 10 revolutions in 100 seconds when a load of 450
W is connected to it, the meter constant (in rev/kWh) is
(a) 1000 (b) 500 (c) 1600 (d) 800
1.17 The minimum number of wattmeter (s) required to measure 3phase, 3wire
balanced or unbalanced power is
(a) 1 (b) 2 (c) 3 (d) 4
1.18 In the singlestage transistor amplifier circuit shown in Fig.P1.18, the capacitor C
E
is removed. Then, the ac smallsignal midband voltage gain of the amplifier
(a) increases (b) decreases
(c) is unaffected (d) drops to zero
1.19. Among the following four, the slowest ADC (analogtodigital converter) is
(a) parallel comparator (i.e., flash) type
(b) successive approximation type
(c) integrating type (d) counting type
1.20. The output of a logic gate is “1” when all its inputs are at logic “0”. The gate is
either
(a) a NAND or an EXOR gate (b) a NOR or an EXOR gate
(c) an AND or an EXNOR gate (d) a NOR or an EXNOR gate
1.21. The output f of the 4to1 MUX shown in Fig.P1.21 is
(a) xy x + (b) x+y (c) x y + (d) xy+x
C E
+12V
Input
Output
+

+
V CC
2
1
0
S 1 S 0
X
Y
MUX
GATE EE  2001
1.22. An opamp has an openloop gain of 10
5
and an openloop upper cutoff frequency
of 10 Hz. If this opamp is connected as an amplifier with a closedloop gain of
100, then the new upper cutoff frequency is
(a) 10 Hz (b) 100 Hz (c) 10 kHz (d) 100 kHz
1.23. The main reason for connecting a pulse transformer at the output stage of a
thyristor triggering circuit is to
(a) amplifying the power of the triggering pulse
(b) provide electrical isolation
(c) reduce the turn on time of the thyristor
(d) avoid spurious triggering of the thyristor due to noise
1.24. ACtoDC circulating current dual converters are operated with the following
relationship between their triggering angles (a
1
and a
2
).
(a) a
1
+ a
2
= 180° (b) a
1
+ a
2
= 360°
(c) a
1
 a
2
= 180° (d) a
1
+ a
2
= 90°
1.25 In case of an armature controlled separately excited dc motor drive with closed
loop speed control, an inner current loop is useful because it
(a) limits the speed of the motor to a safe value
(b) helps in improving the drive energy efficiency
(c) limits the peak current of the motor to the permissible value
(d) reduces the steady state speed error
2. This question consists of TWENTYFIVE subquestions (2.1 – 2.25) of TWO marks
each. For each of these subquestions, four possible alternatives (A, B, C and D)
are given, out of which ONLY ONE is correct. Indicate the correct answer by
darkening the appropriate bubble against the question number on the left hand
side of the Objective Response Sheet (ORS). You may use the answer book
provided for any rough work, if needed.
2.1 The electric field E
ur
(in volts/metre) at the point (1,1,0) due to a point charge of
+1µC located at (1,1,1) (coordinates in metres)is
(a) ( )
6
0
10
2
20 5
i k
pe

 (b) ( )
6
0
10
2
20
i k
pe


(c) ( )
6
0
10
2
20 5
i k
pe


 (d) ( )
6
0
10
2
20
i k
pe



2.2. A connected network of N>2 nodes has at most one branch directly connecting
any pair of nodes. The graph of the network
(a) must have at least N branches for one or more closed paths to exist
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