Electronics and Communication Engineering (EC) 2004 GATE Paper without solution PDF Download

 Page 1


GATE EC - 2004
Q.1 – Q.30 Carry One Mark Each 
1. Consider the network graph shown in figure. Which one of the following is NOT a
‘tree’ of this graph?
(a) (b) 
(c) (d) 
2. The equivalent inductance measured between the terminals 1 and 2 for the
circuit shown in figure, is
(a) 
1 2
L L M + + (b) 
1 2
L L M + - (c) 
1 2
2 L L M + + (d) 
1 2
2 L L M + -
3. The circuit shown in Fig.Q.3, with R =
1 1
, , 3
3 4
L H C F W = = has input voltage 
() sin2 . v t t = The resulting current i(t) is
(a) 
( )
5sin 2 53.1
o
t +
(b) 
( )
5sin 2 53.1
o
t -
(c) 
( )
25sin 2 53.1
o
t +
(d) 
( )
25sin 2 53.1
o
t -
L 1
L 2
1 
M 
2 
C 
L 
R 
i(t) 
v(t) 
Page 2


GATE EC - 2004
Q.1 – Q.30 Carry One Mark Each 
1. Consider the network graph shown in figure. Which one of the following is NOT a
‘tree’ of this graph?
(a) (b) 
(c) (d) 
2. The equivalent inductance measured between the terminals 1 and 2 for the
circuit shown in figure, is
(a) 
1 2
L L M + + (b) 
1 2
L L M + - (c) 
1 2
2 L L M + + (d) 
1 2
2 L L M + -
3. The circuit shown in Fig.Q.3, with R =
1 1
, , 3
3 4
L H C F W = = has input voltage 
() sin2 . v t t = The resulting current i(t) is
(a) 
( )
5sin 2 53.1
o
t +
(b) 
( )
5sin 2 53.1
o
t -
(c) 
( )
25sin 2 53.1
o
t +
(d) 
( )
25sin 2 53.1
o
t -
L 1
L 2
1 
M 
2 
C 
L 
R 
i(t) 
v(t) 
GATE EC - 2004
  
4. For the circuit shown in Fig.Q.4, the time constant RC = 1ms. The input voltage
is ( )
3
2 sin10 .
i
v t t = The output voltage ()
0
v t is equal to
(a)
( )
3
sin 10 45
o
t -
(b) 
( )
3
sin 10 45
o
t +
(c) 
( )
3
sin 10 53
o
t -
(d) 
( )
3
sin 10 53
o
t +
5. For the R-L circuit shown in Fig.Q.5, the input voltage ( ) ().
i
v t u t = The current 
i(t) is
(a) (b) 
(c) (d) 
6. The impurity commonly used for realizing the base region of a silicon n-p-n
transistor is
(a) Gallium (b) Indium (c) Boron (d) Phosphorus
C 
R 
V 1(t) 
V 0(t) 
1H 
2O 
i(t) 
v i(t) 
0.5 
0.31 
2 t(sec) 
i(t) 
1 
0.63 
1/2 t(sec) 
i(t) 
0.5 
0.31 
1/2 t(sec) 
i(t) 
1 
0.63 
2 
t(sec) 
i(t) 
Page 3


GATE EC - 2004
Q.1 – Q.30 Carry One Mark Each 
1. Consider the network graph shown in figure. Which one of the following is NOT a
‘tree’ of this graph?
(a) (b) 
(c) (d) 
2. The equivalent inductance measured between the terminals 1 and 2 for the
circuit shown in figure, is
(a) 
1 2
L L M + + (b) 
1 2
L L M + - (c) 
1 2
2 L L M + + (d) 
1 2
2 L L M + -
3. The circuit shown in Fig.Q.3, with R =
1 1
, , 3
3 4
L H C F W = = has input voltage 
() sin2 . v t t = The resulting current i(t) is
(a) 
( )
5sin 2 53.1
o
t +
(b) 
( )
5sin 2 53.1
o
t -
(c) 
( )
25sin 2 53.1
o
t +
(d) 
( )
25sin 2 53.1
o
t -
L 1
L 2
1 
M 
2 
C 
L 
R 
i(t) 
v(t) 
GATE EC - 2004
  
4. For the circuit shown in Fig.Q.4, the time constant RC = 1ms. The input voltage
is ( )
3
2 sin10 .
i
v t t = The output voltage ()
0
v t is equal to
(a)
( )
3
sin 10 45
o
t -
(b) 
( )
3
sin 10 45
o
t +
(c) 
( )
3
sin 10 53
o
t -
(d) 
( )
3
sin 10 53
o
t +
5. For the R-L circuit shown in Fig.Q.5, the input voltage ( ) ().
i
v t u t = The current 
i(t) is
(a) (b) 
(c) (d) 
6. The impurity commonly used for realizing the base region of a silicon n-p-n
transistor is
(a) Gallium (b) Indium (c) Boron (d) Phosphorus
C 
R 
V 1(t) 
V 0(t) 
1H 
2O 
i(t) 
v i(t) 
0.5 
0.31 
2 t(sec) 
i(t) 
1 
0.63 
1/2 t(sec) 
i(t) 
0.5 
0.31 
1/2 t(sec) 
i(t) 
1 
0.63 
2 
t(sec) 
i(t) 
GATE EC - 2004
  
7. If for a silicon n-p-n transistor, the base-to-emitter voltage (V
BE
) is 0.7V and the
collector-to-base voltage (V
CB
) is 0.2V, then the transistor is operating in the
(a) normal active mode (b) saturation mode 
(c) inverse active mode (d) cutoff mode 
8. Consider the following statements S
1
 and S
2
.
S
1
: The ß of a bipolar transistor reduces if the base width is increased.
S
2
: The ß of a bipolar transistor increases if the doping concentration in the base
in increased 
Which one of the following is correct? 
(a) S
1
 is FALSE and S
2
 is TRUE (b) both S
1 
and S
2
 are TRUE 
(c) both S
1 
and S
2
 are FALSE (d) S
1
 is TRUE and S
2
 is FALSE 
9. An ideal op-amp is an ideal
(a) voltage controlled current source (b) voltage controlled voltage source 
(c) current controlled current source (d) current controlled voltage source 
10. Voltage series feedback (also called series shunt feedback) results in
(a) increase in both input and output impedances
(b) decrease in both input and output impedances
(c) increase in input impedance and decrease in output impedance
(d) decrease in input impedance and increase in output impedance
11. The circuit in Figure is a
(a) low-pass filter (b) high-pass filter 
(c) band-pass filter (d) band-reject filter 
R 
+
- 
C
V
out
R 
C
V
in
Page 4


GATE EC - 2004
Q.1 – Q.30 Carry One Mark Each 
1. Consider the network graph shown in figure. Which one of the following is NOT a
‘tree’ of this graph?
(a) (b) 
(c) (d) 
2. The equivalent inductance measured between the terminals 1 and 2 for the
circuit shown in figure, is
(a) 
1 2
L L M + + (b) 
1 2
L L M + - (c) 
1 2
2 L L M + + (d) 
1 2
2 L L M + -
3. The circuit shown in Fig.Q.3, with R =
1 1
, , 3
3 4
L H C F W = = has input voltage 
() sin2 . v t t = The resulting current i(t) is
(a) 
( )
5sin 2 53.1
o
t +
(b) 
( )
5sin 2 53.1
o
t -
(c) 
( )
25sin 2 53.1
o
t +
(d) 
( )
25sin 2 53.1
o
t -
L 1
L 2
1 
M 
2 
C 
L 
R 
i(t) 
v(t) 
GATE EC - 2004
  
4. For the circuit shown in Fig.Q.4, the time constant RC = 1ms. The input voltage
is ( )
3
2 sin10 .
i
v t t = The output voltage ()
0
v t is equal to
(a)
( )
3
sin 10 45
o
t -
(b) 
( )
3
sin 10 45
o
t +
(c) 
( )
3
sin 10 53
o
t -
(d) 
( )
3
sin 10 53
o
t +
5. For the R-L circuit shown in Fig.Q.5, the input voltage ( ) ().
i
v t u t = The current 
i(t) is
(a) (b) 
(c) (d) 
6. The impurity commonly used for realizing the base region of a silicon n-p-n
transistor is
(a) Gallium (b) Indium (c) Boron (d) Phosphorus
C 
R 
V 1(t) 
V 0(t) 
1H 
2O 
i(t) 
v i(t) 
0.5 
0.31 
2 t(sec) 
i(t) 
1 
0.63 
1/2 t(sec) 
i(t) 
0.5 
0.31 
1/2 t(sec) 
i(t) 
1 
0.63 
2 
t(sec) 
i(t) 
GATE EC - 2004
  
7. If for a silicon n-p-n transistor, the base-to-emitter voltage (V
BE
) is 0.7V and the
collector-to-base voltage (V
CB
) is 0.2V, then the transistor is operating in the
(a) normal active mode (b) saturation mode 
(c) inverse active mode (d) cutoff mode 
8. Consider the following statements S
1
 and S
2
.
S
1
: The ß of a bipolar transistor reduces if the base width is increased.
S
2
: The ß of a bipolar transistor increases if the doping concentration in the base
in increased 
Which one of the following is correct? 
(a) S
1
 is FALSE and S
2
 is TRUE (b) both S
1 
and S
2
 are TRUE 
(c) both S
1 
and S
2
 are FALSE (d) S
1
 is TRUE and S
2
 is FALSE 
9. An ideal op-amp is an ideal
(a) voltage controlled current source (b) voltage controlled voltage source 
(c) current controlled current source (d) current controlled voltage source 
10. Voltage series feedback (also called series shunt feedback) results in
(a) increase in both input and output impedances
(b) decrease in both input and output impedances
(c) increase in input impedance and decrease in output impedance
(d) decrease in input impedance and increase in output impedance
11. The circuit in Figure is a
(a) low-pass filter (b) high-pass filter 
(c) band-pass filter (d) band-reject filter 
R 
+
- 
C
V
out
R 
C
V
in
GATE EC - 2004
  
12. Assuming V
Cesat
=0.2V and ß = 50, the minimum base current (I
B
) required to
drive the transistor in Fig.Q.12 to saturation is
(a) 56 µA
(b) 140 mA
(c) 60 µA
(d) 3 mA
13. A master slave flip-flop has the characteristic that
(a) change in the input immediately reflected in the output
(b) change in the output occurs when the state of the master is affected
(c) change in the output occurs when the state of the slave is affected
(d) both the master and the slave states are affected at the same time
14. The range of signed decimal numbers that can be represented by 6-bite 1’s
complement number is
(a) -31 to +31 (b) -63 to +64 (c) -64 to +63 (d) -32 to +31
15. A digital system is required to amplify a binary-encoded audio signal. The user
should be able to control the gain of the amplifier from a minimum to a maximum
in 100 increments. The minimum number of bits required to encode, in straight
binary is
(a) 8 (b) 6 (c) 5 (d) 7 
16. Choose the correct one from among the alternatives A,B,C,D after matching an
item from Group 1 with the most appropriate item in Group 2.
Group 1 Group 2 
P. Shift register 1. Frequency division
Q. Counter 2. Addressing in memory chips
R. Decoder 3. Serial to parallel data conversion
(a) P – 3  Q – 2  R - 1  (b) P – 3  Q – 1  R - 2 
(c) P – 2  Q – 1  R – 3 (d) P – 1  Q – 2  R - 2 
I C 
1kO 
3V 
I B
Page 5


GATE EC - 2004
Q.1 – Q.30 Carry One Mark Each 
1. Consider the network graph shown in figure. Which one of the following is NOT a
‘tree’ of this graph?
(a) (b) 
(c) (d) 
2. The equivalent inductance measured between the terminals 1 and 2 for the
circuit shown in figure, is
(a) 
1 2
L L M + + (b) 
1 2
L L M + - (c) 
1 2
2 L L M + + (d) 
1 2
2 L L M + -
3. The circuit shown in Fig.Q.3, with R =
1 1
, , 3
3 4
L H C F W = = has input voltage 
() sin2 . v t t = The resulting current i(t) is
(a) 
( )
5sin 2 53.1
o
t +
(b) 
( )
5sin 2 53.1
o
t -
(c) 
( )
25sin 2 53.1
o
t +
(d) 
( )
25sin 2 53.1
o
t -
L 1
L 2
1 
M 
2 
C 
L 
R 
i(t) 
v(t) 
GATE EC - 2004
  
4. For the circuit shown in Fig.Q.4, the time constant RC = 1ms. The input voltage
is ( )
3
2 sin10 .
i
v t t = The output voltage ()
0
v t is equal to
(a)
( )
3
sin 10 45
o
t -
(b) 
( )
3
sin 10 45
o
t +
(c) 
( )
3
sin 10 53
o
t -
(d) 
( )
3
sin 10 53
o
t +
5. For the R-L circuit shown in Fig.Q.5, the input voltage ( ) ().
i
v t u t = The current 
i(t) is
(a) (b) 
(c) (d) 
6. The impurity commonly used for realizing the base region of a silicon n-p-n
transistor is
(a) Gallium (b) Indium (c) Boron (d) Phosphorus
C 
R 
V 1(t) 
V 0(t) 
1H 
2O 
i(t) 
v i(t) 
0.5 
0.31 
2 t(sec) 
i(t) 
1 
0.63 
1/2 t(sec) 
i(t) 
0.5 
0.31 
1/2 t(sec) 
i(t) 
1 
0.63 
2 
t(sec) 
i(t) 
GATE EC - 2004
  
7. If for a silicon n-p-n transistor, the base-to-emitter voltage (V
BE
) is 0.7V and the
collector-to-base voltage (V
CB
) is 0.2V, then the transistor is operating in the
(a) normal active mode (b) saturation mode 
(c) inverse active mode (d) cutoff mode 
8. Consider the following statements S
1
 and S
2
.
S
1
: The ß of a bipolar transistor reduces if the base width is increased.
S
2
: The ß of a bipolar transistor increases if the doping concentration in the base
in increased 
Which one of the following is correct? 
(a) S
1
 is FALSE and S
2
 is TRUE (b) both S
1 
and S
2
 are TRUE 
(c) both S
1 
and S
2
 are FALSE (d) S
1
 is TRUE and S
2
 is FALSE 
9. An ideal op-amp is an ideal
(a) voltage controlled current source (b) voltage controlled voltage source 
(c) current controlled current source (d) current controlled voltage source 
10. Voltage series feedback (also called series shunt feedback) results in
(a) increase in both input and output impedances
(b) decrease in both input and output impedances
(c) increase in input impedance and decrease in output impedance
(d) decrease in input impedance and increase in output impedance
11. The circuit in Figure is a
(a) low-pass filter (b) high-pass filter 
(c) band-pass filter (d) band-reject filter 
R 
+
- 
C
V
out
R 
C
V
in
GATE EC - 2004
  
12. Assuming V
Cesat
=0.2V and ß = 50, the minimum base current (I
B
) required to
drive the transistor in Fig.Q.12 to saturation is
(a) 56 µA
(b) 140 mA
(c) 60 µA
(d) 3 mA
13. A master slave flip-flop has the characteristic that
(a) change in the input immediately reflected in the output
(b) change in the output occurs when the state of the master is affected
(c) change in the output occurs when the state of the slave is affected
(d) both the master and the slave states are affected at the same time
14. The range of signed decimal numbers that can be represented by 6-bite 1’s
complement number is
(a) -31 to +31 (b) -63 to +64 (c) -64 to +63 (d) -32 to +31
15. A digital system is required to amplify a binary-encoded audio signal. The user
should be able to control the gain of the amplifier from a minimum to a maximum
in 100 increments. The minimum number of bits required to encode, in straight
binary is
(a) 8 (b) 6 (c) 5 (d) 7 
16. Choose the correct one from among the alternatives A,B,C,D after matching an
item from Group 1 with the most appropriate item in Group 2.
Group 1 Group 2 
P. Shift register 1. Frequency division
Q. Counter 2. Addressing in memory chips
R. Decoder 3. Serial to parallel data conversion
(a) P – 3  Q – 2  R - 1  (b) P – 3  Q – 1  R - 2 
(c) P – 2  Q – 1  R – 3 (d) P – 1  Q – 2  R - 2 
I C 
1kO 
3V 
I B
GATE EC - 2004
  
1.0 
0.55 
0.25 
F
x
(x) 
-2 0 1 3 
x 
17. Figure shows the internal schematic of a TTL AND-OR-Invert (AOI) gate. For the
inputs shown in Figure, the output Y is
(a) 0
(b) 1
(c) AB 
(d) AB
18. Figure is the voltage transfer characteristic of
(a) an NMOS inverter with enhancement mode
transistor as load  
(b) an NMOS inverter with depletion mode transistor 
as load 
(c) A CMOS inverter 
(d) A BJT inverter 
19. The impulse response h[n] of a linear time-invariant system is given by
[ ] [ ] [ ] [ ] 3 2 2 7 h n u n u n u n = + + - - -
where u[n] is the unit step sequence. The above system is
(a) stable but not causal (b) stable and causal 
(c) causal but unstable (d) unstable and not causal 
20. The distribution function ( )
x
f x of a random variable X is shown in Fig.Q.20. the 
probability that X = 1 is
(a) zero (b) 0.25 (c) 0.55 (d) 0.30 
A 
B 
Y 
Inputs are 
floating 
0 
V in 
V out