Electronics and Communication Engineering - EC 2018 GATE Paper with solution | GATE ECE (Electronics) Mock Test Series 2025 - Electronics and Communication Engineering (ECE) PDF Download

 Page 1


GATE 2018                                                                                            General Aptitude (GA) Set-5  
GA 1/3 
Q. 1 – Q. 5 carry one mark each. 
Q.1  “By giving him the last ______ of the cake, you will ensure lasting _____ in our house 
today. ” 
 
The words that best fill the blanks in the above sentence are 
 
(A) peas, piece (B) piece, peace 
(C) peace, piece (D) peace, peas 
 
 
Q.2  “Even though there is a vast scope for its ________, tourism has remained a/an _________ 
area. ” 
 
The words that best fill the blanks in the above sentence are 
 
(A) improvement, neglected 
(B) rejection, approved 
(C) fame, glum 
(D) interest, disinterested 
 
 
Q.3  If the number 715?423 is divisible by 3 (? denotes the missing digit in the thousandths 
place), then the smallest whole number in the place of ? is _________. 
 
(A) 0 (B) 2 (C) 5 (D) 6 
 
 
Q.4  
What is the value of 1 +
1
4
+
1
16
+
1
64
+ 
1
256
+ ?? 
 
(A) 2 
(B) 
7
4
 (C) 
3
2
 (D) 
4
3
 
 
 
Q.5  A 1.5 m tall person is standing at a distance of 3 m from a lamp post. The light from the 
lamp at the top of the post casts her shadow. The length of the shadow is twice her height. 
What is the height of the lamp post in meters? 
 
(A) 1.5 (B) 3 (C) 4.5 (D) 6 
 
 
Q. 6 – Q. 10 carry two marks each. 
 
Q.6  Leila aspires to buy a car worth Rs. 10,00,000 after 5 years. What is the minimum amount 
in Rupees that she should deposit now in a bank which offers 10% annual rate of interest, if 
the interest was compounded annually? 
 
(A) 5,00,000 (B) 6,21,000 
(C) 6,66,667 (D) 7,50,000 
Page 2


GATE 2018                                                                                            General Aptitude (GA) Set-5  
GA 1/3 
Q. 1 – Q. 5 carry one mark each. 
Q.1  “By giving him the last ______ of the cake, you will ensure lasting _____ in our house 
today. ” 
 
The words that best fill the blanks in the above sentence are 
 
(A) peas, piece (B) piece, peace 
(C) peace, piece (D) peace, peas 
 
 
Q.2  “Even though there is a vast scope for its ________, tourism has remained a/an _________ 
area. ” 
 
The words that best fill the blanks in the above sentence are 
 
(A) improvement, neglected 
(B) rejection, approved 
(C) fame, glum 
(D) interest, disinterested 
 
 
Q.3  If the number 715?423 is divisible by 3 (? denotes the missing digit in the thousandths 
place), then the smallest whole number in the place of ? is _________. 
 
(A) 0 (B) 2 (C) 5 (D) 6 
 
 
Q.4  
What is the value of 1 +
1
4
+
1
16
+
1
64
+ 
1
256
+ ?? 
 
(A) 2 
(B) 
7
4
 (C) 
3
2
 (D) 
4
3
 
 
 
Q.5  A 1.5 m tall person is standing at a distance of 3 m from a lamp post. The light from the 
lamp at the top of the post casts her shadow. The length of the shadow is twice her height. 
What is the height of the lamp post in meters? 
 
(A) 1.5 (B) 3 (C) 4.5 (D) 6 
 
 
Q. 6 – Q. 10 carry two marks each. 
 
Q.6  Leila aspires to buy a car worth Rs. 10,00,000 after 5 years. What is the minimum amount 
in Rupees that she should deposit now in a bank which offers 10% annual rate of interest, if 
the interest was compounded annually? 
 
(A) 5,00,000 (B) 6,21,000 
(C) 6,66,667 (D) 7,50,000 
GATE 2018                                                                                            General Aptitude (GA) Set-5  
GA 2/3 
 
Q.7  Two alloys A and B contain gold and copper in the ratios of 2:3 and 3:7 by mass, 
respectively. Equal masses of alloys A and B are melted to make an alloy C. The ratio of 
gold to copper in alloy C is
 
______. 
 
(A) 5:10 (B) 7:13 (C) 6:11 (D) 9:13 
 
 
Q.8  The Cricket Board has long recognized J ohn’s potential as a leader of the team. However, 
his on-field temper has always been a matter of concern for them since his junior days. 
While this aggression has filled stadia with die-hard fans, it has taken a toll on his own 
batting. Until recently, it appeared that he found it difficult to convert his aggression into 
big scores. Over the past three seasons though, that picture of John has been replaced by a 
cerebral, calculative and successful batsman-captain. After many years, it appears that the 
team has finally found a complete captain. 
 
Which of the following statements can be logically inferred from the above paragraph? 
(i) Even as a junior cricketer, John was considered a good captain. 
(ii) Finding a complete captain is a challenge. 
(iii) Fans and the Cricket Board have differing views on what they want in a captain. 
(iv) Over the past three seasons John has accumulated big scores. 
 
(A) (i), (ii) and (iii) only 
(B) (iii) and (iv) only 
(C) (ii) and (iv) only 
(D) (i), (ii), (iii) and (iv) 
 
 
Q.9  A cab was involved in a hit and run accident at night. You are given the following data 
about the cabs in the city and the accident. 
(i) 85% of cabs in the city are green and the remaining cabs are blue. 
(ii) A witness identified the cab involved in the accident as blue. 
(iii) It is known that a witness can correctly identify the cab colour only 80% of the 
time. 
 
Which of the following options is closest to the probability that the accident was caused by 
a blue cab? 
 
(A) 12% (B) 15% (C) 41% (D) 80% 
 
 
 
 
 
Page 3


GATE 2018                                                                                            General Aptitude (GA) Set-5  
GA 1/3 
Q. 1 – Q. 5 carry one mark each. 
Q.1  “By giving him the last ______ of the cake, you will ensure lasting _____ in our house 
today. ” 
 
The words that best fill the blanks in the above sentence are 
 
(A) peas, piece (B) piece, peace 
(C) peace, piece (D) peace, peas 
 
 
Q.2  “Even though there is a vast scope for its ________, tourism has remained a/an _________ 
area. ” 
 
The words that best fill the blanks in the above sentence are 
 
(A) improvement, neglected 
(B) rejection, approved 
(C) fame, glum 
(D) interest, disinterested 
 
 
Q.3  If the number 715?423 is divisible by 3 (? denotes the missing digit in the thousandths 
place), then the smallest whole number in the place of ? is _________. 
 
(A) 0 (B) 2 (C) 5 (D) 6 
 
 
Q.4  
What is the value of 1 +
1
4
+
1
16
+
1
64
+ 
1
256
+ ?? 
 
(A) 2 
(B) 
7
4
 (C) 
3
2
 (D) 
4
3
 
 
 
Q.5  A 1.5 m tall person is standing at a distance of 3 m from a lamp post. The light from the 
lamp at the top of the post casts her shadow. The length of the shadow is twice her height. 
What is the height of the lamp post in meters? 
 
(A) 1.5 (B) 3 (C) 4.5 (D) 6 
 
 
Q. 6 – Q. 10 carry two marks each. 
 
Q.6  Leila aspires to buy a car worth Rs. 10,00,000 after 5 years. What is the minimum amount 
in Rupees that she should deposit now in a bank which offers 10% annual rate of interest, if 
the interest was compounded annually? 
 
(A) 5,00,000 (B) 6,21,000 
(C) 6,66,667 (D) 7,50,000 
GATE 2018                                                                                            General Aptitude (GA) Set-5  
GA 2/3 
 
Q.7  Two alloys A and B contain gold and copper in the ratios of 2:3 and 3:7 by mass, 
respectively. Equal masses of alloys A and B are melted to make an alloy C. The ratio of 
gold to copper in alloy C is
 
______. 
 
(A) 5:10 (B) 7:13 (C) 6:11 (D) 9:13 
 
 
Q.8  The Cricket Board has long recognized J ohn’s potential as a leader of the team. However, 
his on-field temper has always been a matter of concern for them since his junior days. 
While this aggression has filled stadia with die-hard fans, it has taken a toll on his own 
batting. Until recently, it appeared that he found it difficult to convert his aggression into 
big scores. Over the past three seasons though, that picture of John has been replaced by a 
cerebral, calculative and successful batsman-captain. After many years, it appears that the 
team has finally found a complete captain. 
 
Which of the following statements can be logically inferred from the above paragraph? 
(i) Even as a junior cricketer, John was considered a good captain. 
(ii) Finding a complete captain is a challenge. 
(iii) Fans and the Cricket Board have differing views on what they want in a captain. 
(iv) Over the past three seasons John has accumulated big scores. 
 
(A) (i), (ii) and (iii) only 
(B) (iii) and (iv) only 
(C) (ii) and (iv) only 
(D) (i), (ii), (iii) and (iv) 
 
 
Q.9  A cab was involved in a hit and run accident at night. You are given the following data 
about the cabs in the city and the accident. 
(i) 85% of cabs in the city are green and the remaining cabs are blue. 
(ii) A witness identified the cab involved in the accident as blue. 
(iii) It is known that a witness can correctly identify the cab colour only 80% of the 
time. 
 
Which of the following options is closest to the probability that the accident was caused by 
a blue cab? 
 
(A) 12% (B) 15% (C) 41% (D) 80% 
 
 
 
 
 
GATE 2018                                                                                            General Aptitude (GA) Set-5  
GA 3/3 
Q.10  A coastal region with unparalleled beauty is home to many species of animals. It is dotted 
with coral reefs and unspoilt white sandy beaches. It has remained inaccessible to tourists 
due to poor connectivity and lack of accommodation. A company has spotted the 
opportunity and is planning to develop a luxury resort with helicopter service to the nearest 
major city airport. Environmentalists are upset that this would lead to the region becoming 
crowded and polluted like any other major beach resorts. 
 
Which one of the following statements can be logically inferred from the information given 
in the above paragraph? 
 
(A) The culture and tradition of the local people will be influenced by the tourists. 
(B) The region will become crowded and polluted due to tourism. 
(C) The coral reefs are on the decline and could soon vanish. 
(D) Helicopter connectivity would lead to an increase in tourists coming to the region. 
 
 
END OF THE QUESTION PAPER 
 
Page 4


GATE 2018                                                                                            General Aptitude (GA) Set-5  
GA 1/3 
Q. 1 – Q. 5 carry one mark each. 
Q.1  “By giving him the last ______ of the cake, you will ensure lasting _____ in our house 
today. ” 
 
The words that best fill the blanks in the above sentence are 
 
(A) peas, piece (B) piece, peace 
(C) peace, piece (D) peace, peas 
 
 
Q.2  “Even though there is a vast scope for its ________, tourism has remained a/an _________ 
area. ” 
 
The words that best fill the blanks in the above sentence are 
 
(A) improvement, neglected 
(B) rejection, approved 
(C) fame, glum 
(D) interest, disinterested 
 
 
Q.3  If the number 715?423 is divisible by 3 (? denotes the missing digit in the thousandths 
place), then the smallest whole number in the place of ? is _________. 
 
(A) 0 (B) 2 (C) 5 (D) 6 
 
 
Q.4  
What is the value of 1 +
1
4
+
1
16
+
1
64
+ 
1
256
+ ?? 
 
(A) 2 
(B) 
7
4
 (C) 
3
2
 (D) 
4
3
 
 
 
Q.5  A 1.5 m tall person is standing at a distance of 3 m from a lamp post. The light from the 
lamp at the top of the post casts her shadow. The length of the shadow is twice her height. 
What is the height of the lamp post in meters? 
 
(A) 1.5 (B) 3 (C) 4.5 (D) 6 
 
 
Q. 6 – Q. 10 carry two marks each. 
 
Q.6  Leila aspires to buy a car worth Rs. 10,00,000 after 5 years. What is the minimum amount 
in Rupees that she should deposit now in a bank which offers 10% annual rate of interest, if 
the interest was compounded annually? 
 
(A) 5,00,000 (B) 6,21,000 
(C) 6,66,667 (D) 7,50,000 
GATE 2018                                                                                            General Aptitude (GA) Set-5  
GA 2/3 
 
Q.7  Two alloys A and B contain gold and copper in the ratios of 2:3 and 3:7 by mass, 
respectively. Equal masses of alloys A and B are melted to make an alloy C. The ratio of 
gold to copper in alloy C is
 
______. 
 
(A) 5:10 (B) 7:13 (C) 6:11 (D) 9:13 
 
 
Q.8  The Cricket Board has long recognized J ohn’s potential as a leader of the team. However, 
his on-field temper has always been a matter of concern for them since his junior days. 
While this aggression has filled stadia with die-hard fans, it has taken a toll on his own 
batting. Until recently, it appeared that he found it difficult to convert his aggression into 
big scores. Over the past three seasons though, that picture of John has been replaced by a 
cerebral, calculative and successful batsman-captain. After many years, it appears that the 
team has finally found a complete captain. 
 
Which of the following statements can be logically inferred from the above paragraph? 
(i) Even as a junior cricketer, John was considered a good captain. 
(ii) Finding a complete captain is a challenge. 
(iii) Fans and the Cricket Board have differing views on what they want in a captain. 
(iv) Over the past three seasons John has accumulated big scores. 
 
(A) (i), (ii) and (iii) only 
(B) (iii) and (iv) only 
(C) (ii) and (iv) only 
(D) (i), (ii), (iii) and (iv) 
 
 
Q.9  A cab was involved in a hit and run accident at night. You are given the following data 
about the cabs in the city and the accident. 
(i) 85% of cabs in the city are green and the remaining cabs are blue. 
(ii) A witness identified the cab involved in the accident as blue. 
(iii) It is known that a witness can correctly identify the cab colour only 80% of the 
time. 
 
Which of the following options is closest to the probability that the accident was caused by 
a blue cab? 
 
(A) 12% (B) 15% (C) 41% (D) 80% 
 
 
 
 
 
GATE 2018                                                                                            General Aptitude (GA) Set-5  
GA 3/3 
Q.10  A coastal region with unparalleled beauty is home to many species of animals. It is dotted 
with coral reefs and unspoilt white sandy beaches. It has remained inaccessible to tourists 
due to poor connectivity and lack of accommodation. A company has spotted the 
opportunity and is planning to develop a luxury resort with helicopter service to the nearest 
major city airport. Environmentalists are upset that this would lead to the region becoming 
crowded and polluted like any other major beach resorts. 
 
Which one of the following statements can be logically inferred from the information given 
in the above paragraph? 
 
(A) The culture and tradition of the local people will be influenced by the tourists. 
(B) The region will become crowded and polluted due to tourism. 
(C) The coral reefs are on the decline and could soon vanish. 
(D) Helicopter connectivity would lead to an increase in tourists coming to the region. 
 
 
END OF THE QUESTION PAPER 
 
GATE 2018                                                                                                                                                      Electronics and Communication Engineering 
EC 1/17 
Q. 1 – Q. 25 carry one mark each. 
Q.1  Two identical nMOS transistors  M
1
 and M
2
 are connected as shown below. The circuit is 
used as an amplifier with the input connected between G and S terminals and the output taken 
between D and S terminals. V
bias
 and V
D
 are so adjusted that both transistors are in saturation. 
The transconductance of this combination is defined as ?? ?? = 
?? ?? ?? ?? ?? ????
 while the output 
resistance is  ?? ??  = 
?? ?? ????
?? ?? ?? , where ?? ?? is the current flowing into the drain of M
2
 . Let ?? ?? 1
,
?? ?? 2
  be the transconductances and ?? ?? 1
, ?? ?? 2
 be the output resistances of transistors M
1
 and 
M
2
, respectively.  
 
 
 
Which of the following statements about estimates for ?? ?? and ?? ?? is correct? 
(A)  ?? ?? ˜ ?? ?? 1
.?? ?? 2
.?? ?? 2
  and  ?? ?? ˜ ?? ?? 1
+ ?? ?? 2
. 
(B)  ?? ?? ˜ ?? ?? 1
+ ?? ?? 2
  and  ?? ?? ˜ ?? ?? 1
+ ?? ?? 2
. 
(C)  ?? ?? ˜ ?? ?? 1
  and  ?? ?? ˜ ?? ?? 1
.?? ?? 2
.?? ?? 2
. 
(D)  ?? ?? ˜ ?? ?? 1
  and  ?? ?? ˜ ?? ?? 2
. 
 
Q.2  In the circuit shown below, the op-amp is ideal and Zener voltage of the diode is 2.5 volts. 
At the input, unit step voltage is applied, i.e. ?? ????
(?? )= ?? (?? ) volts. Also, at ?? = 0, the 
voltage across each of the capacitors is zero. 
 
 
The time ?? , in  millisec onds, at which the output voltage ?? ?????? crosses -10 V  is 
(A)   2.5 (B)   5 (C)   7.5 (D)   10 
 
Q.3  A good transimpedance amplifier has  
(A)   low input impedance and high output impedance. 
(B)   high input impedance and high output impedance. 
(C)   high input impedance and low output impedance. 
(D)   low input impedance and low output impedance. 
 
  
Page 5


GATE 2018                                                                                            General Aptitude (GA) Set-5  
GA 1/3 
Q. 1 – Q. 5 carry one mark each. 
Q.1  “By giving him the last ______ of the cake, you will ensure lasting _____ in our house 
today. ” 
 
The words that best fill the blanks in the above sentence are 
 
(A) peas, piece (B) piece, peace 
(C) peace, piece (D) peace, peas 
 
 
Q.2  “Even though there is a vast scope for its ________, tourism has remained a/an _________ 
area. ” 
 
The words that best fill the blanks in the above sentence are 
 
(A) improvement, neglected 
(B) rejection, approved 
(C) fame, glum 
(D) interest, disinterested 
 
 
Q.3  If the number 715?423 is divisible by 3 (? denotes the missing digit in the thousandths 
place), then the smallest whole number in the place of ? is _________. 
 
(A) 0 (B) 2 (C) 5 (D) 6 
 
 
Q.4  
What is the value of 1 +
1
4
+
1
16
+
1
64
+ 
1
256
+ ?? 
 
(A) 2 
(B) 
7
4
 (C) 
3
2
 (D) 
4
3
 
 
 
Q.5  A 1.5 m tall person is standing at a distance of 3 m from a lamp post. The light from the 
lamp at the top of the post casts her shadow. The length of the shadow is twice her height. 
What is the height of the lamp post in meters? 
 
(A) 1.5 (B) 3 (C) 4.5 (D) 6 
 
 
Q. 6 – Q. 10 carry two marks each. 
 
Q.6  Leila aspires to buy a car worth Rs. 10,00,000 after 5 years. What is the minimum amount 
in Rupees that she should deposit now in a bank which offers 10% annual rate of interest, if 
the interest was compounded annually? 
 
(A) 5,00,000 (B) 6,21,000 
(C) 6,66,667 (D) 7,50,000 
GATE 2018                                                                                            General Aptitude (GA) Set-5  
GA 2/3 
 
Q.7  Two alloys A and B contain gold and copper in the ratios of 2:3 and 3:7 by mass, 
respectively. Equal masses of alloys A and B are melted to make an alloy C. The ratio of 
gold to copper in alloy C is
 
______. 
 
(A) 5:10 (B) 7:13 (C) 6:11 (D) 9:13 
 
 
Q.8  The Cricket Board has long recognized J ohn’s potential as a leader of the team. However, 
his on-field temper has always been a matter of concern for them since his junior days. 
While this aggression has filled stadia with die-hard fans, it has taken a toll on his own 
batting. Until recently, it appeared that he found it difficult to convert his aggression into 
big scores. Over the past three seasons though, that picture of John has been replaced by a 
cerebral, calculative and successful batsman-captain. After many years, it appears that the 
team has finally found a complete captain. 
 
Which of the following statements can be logically inferred from the above paragraph? 
(i) Even as a junior cricketer, John was considered a good captain. 
(ii) Finding a complete captain is a challenge. 
(iii) Fans and the Cricket Board have differing views on what they want in a captain. 
(iv) Over the past three seasons John has accumulated big scores. 
 
(A) (i), (ii) and (iii) only 
(B) (iii) and (iv) only 
(C) (ii) and (iv) only 
(D) (i), (ii), (iii) and (iv) 
 
 
Q.9  A cab was involved in a hit and run accident at night. You are given the following data 
about the cabs in the city and the accident. 
(i) 85% of cabs in the city are green and the remaining cabs are blue. 
(ii) A witness identified the cab involved in the accident as blue. 
(iii) It is known that a witness can correctly identify the cab colour only 80% of the 
time. 
 
Which of the following options is closest to the probability that the accident was caused by 
a blue cab? 
 
(A) 12% (B) 15% (C) 41% (D) 80% 
 
 
 
 
 
GATE 2018                                                                                            General Aptitude (GA) Set-5  
GA 3/3 
Q.10  A coastal region with unparalleled beauty is home to many species of animals. It is dotted 
with coral reefs and unspoilt white sandy beaches. It has remained inaccessible to tourists 
due to poor connectivity and lack of accommodation. A company has spotted the 
opportunity and is planning to develop a luxury resort with helicopter service to the nearest 
major city airport. Environmentalists are upset that this would lead to the region becoming 
crowded and polluted like any other major beach resorts. 
 
Which one of the following statements can be logically inferred from the information given 
in the above paragraph? 
 
(A) The culture and tradition of the local people will be influenced by the tourists. 
(B) The region will become crowded and polluted due to tourism. 
(C) The coral reefs are on the decline and could soon vanish. 
(D) Helicopter connectivity would lead to an increase in tourists coming to the region. 
 
 
END OF THE QUESTION PAPER 
 
GATE 2018                                                                                                                                                      Electronics and Communication Engineering 
EC 1/17 
Q. 1 – Q. 25 carry one mark each. 
Q.1  Two identical nMOS transistors  M
1
 and M
2
 are connected as shown below. The circuit is 
used as an amplifier with the input connected between G and S terminals and the output taken 
between D and S terminals. V
bias
 and V
D
 are so adjusted that both transistors are in saturation. 
The transconductance of this combination is defined as ?? ?? = 
?? ?? ?? ?? ?? ????
 while the output 
resistance is  ?? ??  = 
?? ?? ????
?? ?? ?? , where ?? ?? is the current flowing into the drain of M
2
 . Let ?? ?? 1
,
?? ?? 2
  be the transconductances and ?? ?? 1
, ?? ?? 2
 be the output resistances of transistors M
1
 and 
M
2
, respectively.  
 
 
 
Which of the following statements about estimates for ?? ?? and ?? ?? is correct? 
(A)  ?? ?? ˜ ?? ?? 1
.?? ?? 2
.?? ?? 2
  and  ?? ?? ˜ ?? ?? 1
+ ?? ?? 2
. 
(B)  ?? ?? ˜ ?? ?? 1
+ ?? ?? 2
  and  ?? ?? ˜ ?? ?? 1
+ ?? ?? 2
. 
(C)  ?? ?? ˜ ?? ?? 1
  and  ?? ?? ˜ ?? ?? 1
.?? ?? 2
.?? ?? 2
. 
(D)  ?? ?? ˜ ?? ?? 1
  and  ?? ?? ˜ ?? ?? 2
. 
 
Q.2  In the circuit shown below, the op-amp is ideal and Zener voltage of the diode is 2.5 volts. 
At the input, unit step voltage is applied, i.e. ?? ????
(?? )= ?? (?? ) volts. Also, at ?? = 0, the 
voltage across each of the capacitors is zero. 
 
 
The time ?? , in  millisec onds, at which the output voltage ?? ?????? crosses -10 V  is 
(A)   2.5 (B)   5 (C)   7.5 (D)   10 
 
Q.3  A good transimpedance amplifier has  
(A)   low input impedance and high output impedance. 
(B)   high input impedance and high output impedance. 
(C)   high input impedance and low output impedance. 
(D)   low input impedance and low output impedance. 
 
  
GATE 2018                                                                                                                                                      Electronics and Communication Engineering 
EC 2/17 
Q.4  Let the input be u and the output be y of a system, and the other parameters are real 
constants. Identify which among the following systems is not a linear system: 
(A)     
3 2 2
1 2 3 3 2 1 3 2 2
d y d y d y du d u
a a a y b u b b
dt dt dt dt dt
? ? ? ? ? ?   (with initial rest conditions) 
(B)     
? ?
? ?
? ?
0
t
t
y t e u d
??
? ? ?
?
?
?
  
(C)     ,0 y au b b ? ? ?  
(D)     y au ?  
 
Q.5  The Nyquist stability criterion and the Routh criterion both are powerful analysis tools for 
determining the stability of feedback controllers. Identify which of the following statements 
is FALSE: 
(A)  Both the criteria provide information relative to the stable gain range of the system. 
(B)  The general shape of the Nyquist plot is readily obtained from the Bode magnitude plot 
for all minimum-phase systems. 
(C)  The Routh criterion is not applicable in the condition of transport lag, which can be 
readily handled by the Nyquist criterion. 
(D)  The closed-loop frequency response for a unity feedback system cannot be obtained 
from the Nyquist plot. 
 
Q.6  Consider ?? (?? )= ?? 3
+ ?? 2
?? 2
+ ?? 1
?? + ?? 0
 with all real coefficients. It is known that its 
derivative ?? '(?? ) has no real roots. The number of real roots of ?? (?? ) is  
(A)  0 (B)  1 (C)  2 (D)  3 
 
Q.7  In a p-n junction diode at equilibrium, which one of the following statements is  
NOT TRUE? 
(A) The hole and electron diffusion current components are in the same direction. 
(B) The hole and electron drift current components are in the same direction. 
(C) On an average, holes and electrons drift in opposite direction. 
(D) On an average, electrons drift and diffuse in the same direction.