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7/25/2019 GATEFORUM ECE QUESTION PAPER

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1

General Aptitude

Q. No. 1-5 Carry One Mark Each

1. At the farewell function, the dignitary's address to the young graduates was _______, offering

no new words of wisdom but common knowledge.

(A) ambivalent (B) platitudinous (C) approbrious (D) pragmatic

2. The administration discussed whether the number of students studying European languages

was likely to decline when the senior lecturer retired.

(A) whether the number of students studying European languages was likely

(B) whether the number of students studying European languages were likely

(C) if the students studying European languages were likely

(D) if the number of European language students were likely

3. Select the word most similar in meaning to the word Unprepossessing

(A)Ugly (B) Arrogant (C) Personable (D) Didactic

4. Each day after an item is lost the probability of finding that item is halved. If 3 days after a

certain item is lost the probability is 1/64, what was the initial probability of finding the item?

(A) 1/32 (B) 1/8 (C) 1/4 (D) 1/2

5. What is the sum of all 4-digit numbers that can be formed using the digits 1,2,3,4 where

repetition of digits is allowed?

Q. No. 6-10 Carry Two Mark Each

6. How many different ways can 2 children be seated in a row of 4 chairs, so that there is always

at least one empty chair between the students?

7. Larry purchased 24 servers and 10 database software licenses. If the cost of each server is ten

times the cost of each database software license, what percent of the total purchase price was

the cost of all of the database software licenses?

8. Which natural number is nearest to 9217 which is completely divisible by 88?(A) 9240 (B) 9152 (C) 9064 (D) 9184

9. On a recent expedition to a remote region of northern Canada, scientists uncovered skeletal

remains from about 100,000 years ago. Surprisingly, all the skeletal remains, which included

many species from differing biological families and spanned about two thousand years,

showed evidence of experiencing temperatures in excess of 1000 degrees Fahrenheit (or 538

degrees Celsius).

Which of the following, if true, best explains the apparent paradox between the cold

environment and the evidence of the bones experiencing hot temperatures?

(A)Chemical changes that naturally occur during the process of decay in only one north


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2

Canadian species produce the same evidence of the species' skeletons being exposed to

hot temperatures as the expedition scientists found.

(B)A little over 103,000 years ago, a large fire is known to have occurred in northern

Canada.

(C) Strong evidence exists that as early as 70,000 years ago, Homo sapiens around the world

relied heavily on fire to cook animals.

(D) In the same expedition and in roughly the same layer of excavation, scientists found

rudimentary wood cutting and hunting tools used by early humans.

10. Choose the best order for the sentences given. The best order is one which will result in a

coherent paragraph.

p. A German called Gutenberg set up the first printing press in the city of Maintz (inGermany) in 1455

q. The first book to be printed outside China was the Bible, in German;r. He used movable type mode of metals. In Europe the first books were printed only in the fifteenth century

The best order is(A) p - q - r - s (B) q - r - p s (C) s - p - r - q (D) s - q - p - r

Electronics and Communication Engineering

Q. No. 1 25 Carry One Mark Each

1. An array of two dipoles is separated by half wavelength. If the dipoles are fed by a current of

same magnitude with phase difference of45 then angle where the nulls of the pattern occur is

(A) 1 3cos8

(B) 1 3cos4

(C) 1 1cos8

(D) 1 1cos4

2. Consider two statements and choose the correct option (True/false)

S1:For a system to be stable, all the coefficients of the characteristic equation must be

Positive and be of the same sign

S2:If a system is to stable, there should not be any sign change in the first column of the

Rouths array

(A)(T, T) (B) (T, F) (C) (F, T) (D) (F, F)

I 4 5 d2

I


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3

3. Consider the following statements relating the Bleeder resistor used in L filter.

(1) Bleeder resistor is connected across the output terminal of power supply

(2) The bleeder resistor is used to maintain minimum current for better voltage regulation.

(3) If bleeder circuit is not there is case of load to be open circuited, no filtering can be done.

Which of the above statements are correct?

(A) 1 and 2 (B) 2 and 3 (C) 1 and 3 (D) 1, 2 and 3

4. Consider the circuit shown below. Load power in the circuit is ________W.

5. If X follows normal distribution with mean 2 and variance 1 then P(X


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4

8. If A = 0 and total number of gates used is 24, output at the end of 24th

gate in the series is

__________.

9. The system y(t) = x(sint) is

(A) Non causal and linear (B) Non causal and non linear

(C) Causal and linear (D) Causal and non linear

10. Consider the BJT amplifier circuit shown below. Which of the following frequencycharacteristics are correct?

20 5010 0

40 10 j

60

10 j 20 50

A

10 0

20 5 j

60

10 j

B

10 0

20 5 j

30

20 j 20 50

C

10 0

20 5 j

30

20 j

D

20 50

20 10 j

30

10 j

20 5010 0

A

1XOR

1

Ex-NOR XOR Ex-NOR

1 1 1 1 1 1


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5

(A) (B)

(C) (D) None of the above

11. The Random variable X and Y joint density function is defined by

c 2x y 2 x 6 , 0 y 5

f x , y0 otherwise

Then P x y 4 is _________.

12. If 10V is applied across a 4cm long semiconductor bar and the average drift velocity is42 10 cm s, the electron mobility is __________ cm2/V-s.

0

i

V

V

k

f

0

i

V

V

k

Lf Hf

0

i

V

V

k

Hf f

0V

C CV

iV

CR


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6

13. Match the following

List-I List-II

a b c d3 1 2 5

4 3 1 5

4 1 2 5

3 4 1

A

B

C

D 5

14. Consider an op-amp shown below

What is the value of R0?

(A) (B) 0 (C) 2R (D) 2R

R R

0V

0R

LI

L o ad~IV L

V

2 R2 R

Im

Re 0

Re

Im

0

Re

Im

0

0

Im

Re

(c)

(b)

(d)

(a)

1

k5.

s(1+sT )

1

k4.

(1-sT )

1

k3.(1+sT )

1 2 3

k2.

(1+sT )(1+sT )(1+sT )

1 2

k1.

(1 sT )(1 sT )


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7

15. The step response plot of three first order systems are shown below along with their possible

transfer functions. Find the suitable match for the curve and there corresponding transfer

function.

1 2 3

2 5 10H (s) , H (s) , H (s)

s 0.2 s 0.5 s 1

(A)1 2 3

H (s) curve X, H (s) curve Y, H (s) curve Z

(B)1 2 3

H (s) curve Z, H (s) curve Y, H (s) curve X

(C)1 2 3

H (s) curve Y, H (s) curve X,H (s) curve Z.

(D) In sufficient information to distinguish the system.

16. In a broadcast super heterodyne receiver having no RF Amplifier the loaded Q of the Antennacoupling circuit (at the input of the mixer) is 80 if IF frequency is 455 kHz. The rejection ratiois _________ at 1000 kHz.

17. Match the following

(1) Gauss law (a) H.ds I.d l

(2) Amperes law (b) 2 0

(3) Poisson equation (c) 2E

(4) Laplace equation (d) D.d dv

(A) 1 d, 2 a, 3 c, 4 b (B) 1 a, 2 d, 3 b, 4 c

(C) 1 a, 2 d, 3 c, 4 b (D) 1 d, 2 a, 3 b, 4 c

18. Consider the network shown below.

1 0

C u r v e Z

C u r v e Y

C u r v e X

t ( s e c )

y ( t )

3H

4V2A2


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8

The power consumed by the 2 resistor is __________W.

19. The energy in the derivative of the following signal is __________J.

20. Fourier transform of the signal x(t) = u(1-|t|) is ________.

(A)2

sin

(B)1

sin

(C)4

sin

(D)0.5

sin

21. Using Eulers method to solve the D.E4 x

y 2cos y, y(0) 13

with step size h=0.25 the

value of y(0.5) is ___________.

22. Assertion (A): An LC circuit can produce undamped sinusoidal oscillations forever

Reason (R): The resistor R is the dissipating element in an RLC circuit

(A) Both A & R are true and R is the correct explanation of A

(B) Both A & R are true and R is not the correct explanation of A

(C) A is true, R is false

(D) A is false but R is true

23. The energy band diagram of a Si sample doped with 17 32 10 atoms cm will be:

10 3

iTake n 1.5 10 cm

(A) (B)

FE

CE

iE

VE

0.324eVFE

CE

iE

VE

0.424eV

f t9

3 66 3 t


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9

(C) (D)

24. The Fourier co-efficient of the signal k

x n n 4k

is represented by Ck. Then Ck is______.

(A)1

;0 k 34

(B)1

k4

(C)1

k16

(D)1

;0 k 316

25. An 8085 microprocessor based system uses RAM whose starting address is AA00 H. The

address of Last byte in this RAM is B9FF H, then the size of RAM is__________ K 8 bit.

Q. No. 26 55 Carry Two Marks Each

26. If2 2 2

x yF x y a y a , circulation of vector field F around closed path shown in figure is

_________.

27. For a line charge 9L (10 / 2)C / m on the z-axis the value of VABis ________ V, where A

is 2m, , 02

and B is 4m, ,5m

28. Find the output y of the following circuit.

C

D0I

1I

2I

3I

y

A B

4 1 M U X

FE

CE

iE

VE

0.417eVFE

CE

iE

VE

0.407eV

2

2

y

x


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10

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

(C) Both A & B (D) y A B C D

29. The solution of the Differential equation 2 2 2dy

x x xy + ydx is

(A)y

Tan lnx + cx

(B)-1 yTan x + c

x

(C)-1 yTan Tan x + c

x

(D) -1 yTan ln x + c

x

30. A frame consisting of 8 bits is being transmitted. The first half of the frame is represented by

bipolar NRZ signaling and 2nd

half by unipolar RZ signaling. Which of the following is the

correct electrical representation of the frame [10110010]?

31.1 2 3

f , f , f and f are canonical SOP form for the circuit.

1

2

3

1 2 3

f m 2,3,8,9

f m 1,3,7,8,9,10

f m 1,7,8

f m a , a , a .....

A 1 2 3 4 56

7 8

C 1 2 3 4 5 6 7 8

D 1 2 3 4 5 6 7 8

1f

2f

3f

4f

5f

f

B 1 2 3 45

6 7

8


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11

The value ofi 1 2 3

a a a a .... is ________.

32. Determine the frequency of oscillation of the circuit shown in figure also calculate value of R1

to make frequency as 20 kHz.

(A) 8.25kHz,4.13k (B) 8.25kHz, 33k

(C) 8.25kHz, 10k (D) None

33. Response of an LTI system to a input signal

nn 1, n 0,1, 2 0.5 , n 0,1, 2

x n , y n0, elsewhere 0, elsewhere

Then if input 1n 1 n 0,1, 2

x n 4 n 2 n 3, 4,5

0 elsewhere

then y1[n] is

(A)

n

n

1

0.5 n 0,1, 2

y n 16 0.5 n 3, 4,5

0 elsewhere

(B) n

1

16 0.5 n 0,1, 2, 3, 4, 5y n

0 elsewhere

(C)

n

n 1

1

0.5 n 0,1, 2

y n 32 0.5 n 3, 4,5

0 elsewhere

(D)

n

n

1

0.5 n 0,1, 2

y n 32. 0.5 n 3, 4,5

0 elsewhere

1R

2R 33k

C 0.01 F

outV

3R 10k


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12

34. Find y-parameters for the following network

(A)4 3

2 3

(B)3 3

2 4

(C)

1 12 2

1 23 3

(D)

2 13 2

1 13 2

35. Consider the system shown in the figure below. If the system is observable, then T T TC : A C is

________.

36. The driving point admittance function of the following network is

1V

2V

20 .5 V

1

1

1

2I1I

I s 5H

V S 2 F

10

2x

1x

y

.

1x

.

2 x

1u

2u

1 / s

1 / s

1

2

1

1


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13

(A)2

20s 1

100s 5s 10

(B)2

20s 1

10s 5s 10

(C)2100s 5s 10

50s

(D)

210s 5s 10

20s 1

37. Consider a periodic signal S(t)

Then period oft t

y(t) 2S S is ________ .3 5

38. Consider a discrete memory less channel as shown below:

P x 0 0.9

P x 0 0.1

The decision rule for optimum receiver is

(A)

y p q r

x 0 0 1 (B)

y p q r

x 0 0 0 (C)

y p q r

x 1 0 0 (D)

y p q r

x 1 1 1

39. For the circuit shown in figure the cut in voltage of diode is V 0.7V . Then plot for 0V

versus iV is;

x 0

x 1

y r

y q

y p

0.5

0.4

0.10.2

0.5

0.3

2k

15V

1k

1V

iV

1kO

V

1

1

1 . 0 0 . 5

0 . 5 1 . 0 t

S t

22


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14

40. Let the Eigen values of a square matrix A of order 2 be 1, 6. The corresponding Eigen vectors

are1 1

and1 4

respectively. Then the element a21 is _______.

41. x1[n] = {1,2,3,4], x2[n] = {2,1,2,1,2]. Then circular convolution of 1 2x n x n is

(A) {17,15,18,16,14] (B) {2,5,10,16,14]

(C) {2,5,10,16,14,15,10,18] (D) None of these

42. The value ofs

r.Nds is ________. Where r x i yj zk and s is the closed surface

enclosing a volume V.

(A) V (B) 2V (C) 3V (D) 4V

43. A constant current of I Amp flows through a diode. What is the value of change in forward

voltage (in mV) if an identical diode is connected in parallel? Given V T= 26mV and 1 .

OV

B

19.6

4.3

4.3 15 i

V

A

19.6

OV

5.7

5.7 iV40.5

C19.6

OV

5.47

5.7 iV15

D9.42

OV

4.3

4.3 i

V15


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15

44. The total energy associated in a system of 4 identical charges of Q = 3nC, at the corners 1m

on a side is approximately equals to ________nJ.

45. A silicon PN junction at T = 300K with zero applied bias has doping concentration of15 3 16 3

a d

N 5 10 cm and N 5 10 cm . The width of depletion region extending into the n-

region is __________ 610 cm. (Given = 11.7 for Si) 10 3in 1.5 10 cm )

46. 40nC of charge is uniformly distributed around a circular ring of radius 2m. Then the

potential at a point on the axis 5m from the plane of the ring is _________ V.

47. In a p-type semiconductor MOS capacitor structure, which of the following energy band

diagram represents depletion mode?

(A)

(B)

(C)

P type semiconductor

CE

FiE

FE

VE

Metal

oxide

dX

Metal

CE

iFE

FE

VE

Oxide

P type semiconductorCE

FiE

FE

VEMetal

oxide

dX


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16

(D)

48. For a unity negative feedback system, with open loop transfer function

KG S

S S 2 S 4

range of k for damped oscillator response is

(A) 3.1 K 48 (B)3.1 K 48 (C)1 K 4.8 (D)1 K 4.8

49. The initial state of the following sequential circuit is A =0, B = 0, & C = 0.

The sequence at the output C for the next seven clock pulses is _________.

(A)1011100 (B) 1100110 (C) 0111000 (D) 1010100

50. A GSM base station need to support 95 users GSM signal in time division multiplexed

between 8 users occupying the common bandwidth of 200 kHz. The total bandwidth required

for 99 users will be ________kHz.

51. Let x(t) be a signal band limited to B Hz. y(t) = x(t). x(t-1) + x(t/2)+3x(3t).

Then minimum sampling rate for y(t) to avoid aliasing in y(t) is ____ B samples/sec.

52. The electric field in the space charge region of uniformly doped np junction is given

below; the potential difference across the depletion is given by

Metal

CE

iFE

FE

VE

Oxide P type semiconductor

AT A

A

BD B

B

CS C

CR CCLK


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(A)AW

4 (B)

2A

W (C)

AW

2 (D) AW

53. For the unity feedback system, the open loop transfer function is

210 s 2

G s s s 1 s 10

The

steady state error for the system when the input 2r t 1 4t 10t u t is_________.

54. A zero added to the plant

5kG s

s 1 s 4

such that the resulting root locus passes

through the point 4 2 j. The position of the zero in the below system is at _______.

55. The magnitude 0A , 2 B 2 B

A0 otherwise

and phase

2, 0

2, 0

0 otherwise

of a Fourier Transform are given. Then the inverse Fourier Transform is

(A) 0A cos 2 Bt 1t

(B) 0A cos 2 Bt 1

2 t

(C) 0A

cos2 Bt 12 t

(D) 0A

cos 2 Bt 1t

W

2

W2

x m

E V kcmA

As B G s

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