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MOCK TEST 1/16 MOCK TEST FIRST WWW.GATEHELP.COM EC : ELECTRONIC AND COMMUNICATION ENGINEERING Duration : Three Hours Maximum Marks : 100 Read the following instructions carefully. 1. Do not open the seal of the Question Booklet unlit you are asked to do so by the invigilator. 2. Take out the Optical Response Sheet (ORS) from this Question Booklet without breaking the seal and read the in- struments printed on the ORS carefully. If you find the Question Booklet Code printed at the right hand top corner of this page does not match with the Booklet Code on the ORS, exchange the booklet immediately with a new sealed Question Booklet. 3. On the right half of the ORS, using ONLY a black ink ball point pen, (i) darken the bubble corresponding to your test paper code and the appropriate bubble under each digit of your registration number and (ii) write your registration number, your name and name of the examination center and put your signature at the specified location. 4. This Question Booklet contain 16 pages including blank pages for rough work. After you are permitted to open the seal, please check all pages and report discrepancies, if any, to the invigilator. 5. There are a total of 65 Question carrying 100 marks. All these questions are of objective type. Each question has only on correct answer. Question must be answered on the left hand side of the ORS by darkening the appropriate bubble (marked A, B, C, D) using ONLY a black ink ball point pen against the question number. For each question darken the bubble of the correct answer. More than on answer bubbled against a question will be treated as an incorrect response. 6. Since bubbles darkened by the black ink ball point pen cannot be erased, candidates should darken the bubbles in the ORS very carefully. 7. Question Q. 1 Q. 25 carry 1 mark each. Questions Q. 26 - Q. 55 carry 2 marks each. The 2 marks question include two pairs of common data questions and two pairs of linked answer questions. The answer of the second question of the linked answer questions depends on the answer to the first question of the pair. If the first question in the linked pair is wrongly answered or is unattemped, then the answer to the second question in the pair will not be evaluated. 8. Question Q. 56 - Q. 65 belong to General Aptitude (GA) section and carry a total of 15 marks. Question Q. 56 - Q.60 carry 1 mark each, and questions Q. 61 -Q. 65 carry 2 marks each. 9. Unattempted questions will result in zero mark and wrong answer will result in NEGATIVE marks. For all 1 mark questions / 1 3 mark will be deducted for each wrong answer. For all 2 marks questions, / 2 3 mark will be deducted for each wrong answer. However, in the case of the linked answer question pair, there will be negative marks only for wrong answer to the first question and no negative marks for wrong answer to the second question. 10. Calculator is allowed whereas charts, graph sheets or tables are NOT allowed in the examination hall. 11. Rough work can be done on the question paper itself. Blank pages are provided at the end of the question paper for rough work. 12. Before the start of the examination, write your name and registration number in the space provided below using a blank ink ball point pen. Names Registration Number EC For Answer Key and Full Solution mail to [email protected].

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Page 1: MOCK TEST-5

MOCK TEST 1/16

MOCK TEST FIRST WWW.GATEHELP.COM

EC : ELECTRONIC AND COMMUNICATION ENGINEERING

Duration : Three Hours Maximum Marks : 100

Read the following instructions carefully.

1. Do not open the seal of the Question Booklet unlit you are asked to do so by the invigilator.

2. Take out the Optical Response Sheet (ORS) from this Question Booklet without breaking the seal and read the in-struments printed on the ORS carefully. If you find the Question Booklet Code printed at the right hand top corner of this page does not match with the Booklet Code on the ORS, exchange the booklet immediately with a new sealed Question Booklet.

3. On the right half of the ORS, using ONLY a black ink ball point pen, (i) darken the bubble corresponding to your test paper code and the appropriate bubble under each digit of your registration number and (ii) write your registration number, your name and name of the examination center and put your signature at the specified location.

4. This Question Booklet contain 16 pages including blank pages for rough work. After you are permitted to open the seal, please check all pages and report discrepancies, if any, to the invigilator.

5. There are a total of 65 Question carrying 100 marks. All these questions are of objective type. Each question has only on correct answer. Question must be answered on the left hand side of the ORS by darkening the appropriate bubble (marked A, B, C, D) using ONLY a black ink ball point pen against the question number. For each question darken the bubble of the correct answer. More than on answer bubbled against a question will be treated as an incorrect response.

6. Since bubbles darkened by the black ink ball point pen cannot be erased, candidates should darken the bubbles in the ORS very carefully.

7. Question Q. 1 Q. 25 carry 1 mark each. Questions Q. 26 - Q. 55 carry 2 marks each. The 2 marks question include two pairs of common data questions and two pairs of linked answer questions. The answer of the second question of the linked answer questions depends on the answer to the first question of the pair. If the first question in the linked pair is wrongly answered or is unattemped, then the answer to the second question in the pair will not be evaluated.

8. Question Q. 56 - Q. 65 belong to General Aptitude (GA) section and carry a total of 15 marks. Question Q. 56 - Q.60 carry 1 mark each, and questions Q. 61 -Q. 65 carry 2 marks each.

9. Unattempted questions will result in zero mark and wrong answer will result in NEGATIVE marks. For all 1 mark questions /1 3 mark will be deducted for each wrong answer. For all 2 marks questions, /2 3 mark will be deducted for each wrong answer. However, in the case of the linked answer question pair, there will be negative marks only for wrong answer to the first question and no negative marks for wrong answer to the second question.

10. Calculator is allowed whereas charts, graph sheets or tables are NOT allowed in the examination hall.

11. Rough work can be done on the question paper itself. Blank pages are provided at the end of the question paper for rough work.

12. Before the start of the examination, write your name and registration number in the space provided below using a

blank ink ball point pen.

Names

Registration Number EC

For Answer Key and Full Solution mail to [email protected].

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Q.1- Q.25 carry one mark each.

Q.1 e

dx1x −# is equal to

(A) ( 1)log ex − (B) (1 )log ex−

(C) ( 1)log e x −− (D) (1 )log e x− −

Q.2 Expand the function ( )( )z z1 2

1− − in laurent’s series for 1z <

(A) 1 3 ...z z z27

4152 2+ + + (B) ...z z z2

143

87

16152 3+ + +

(C) ...z z41

43

8 162 3

+ + + (D) None of the above

Q.3 If A is a square matrix of order 3 and 2A = then A(adjA) is equal to

(A) 02

00

020

02

R

T

SSSS

V

X

WWWW

(B) 0 0

00 0

021

21

21

R

T

SSSS

V

X

WWWW

(C) 0 01

00

10

01

R

T

SSSS

V

X

WWWW

(D) None of these

Q.4 Consider a ufb system with forward-path transfer function ( )G s ( )( )

s sK s

23

4=++

. The system is stable for the range of K ;(A) 0K > (B) 0K <

(C) 1K > (D) Always unstable

Q.5 The time signal corresponding to s ss s

5 62 10 11

2

2

+ ++ + is

(A) 2 ( ) ( ) ( )t e e u tt t3 2δ + −− − (B) 2 ( ) ( ) ( )t e e u tt t2 3δ + −− −

(C) 2 ( ) ( ) ( )t e e u tt t2 3δ + +− − (D) 2 ( ) ( ) ( )t e e u tt t2 3δ − +− −

Q.6 The characteristic equation of a closed-loop system is ( 1)( 2) 0s s s K+ + + = . The centroid of the asymptotes in toot-locus will be(A) 3 (B) 1−

(C) 1 (D) 3−

Q.7 Given the z −transforms ( )X z ( )

z zz z

4 7 38 7

2=− +

− the limit of [ ]x 3 is

(A) 1 (B) 2

(C) 3 (D) 0

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Q.8 For the block diagram shown below transfer function ( )/ ( )C s R s is

(A) G G G G G G G G G G G G G GG G

1 1 2 1 7 3 1 2 8 6 1 2 3 7 5

1 2

+ + + +

(B) G G G G G G G G G G G G G GG G

1 1 4 1 2 8 1 2 5 7 1 2 3 6 7

1 2

+ + + +

(C) G G G G G G G G G G G G G GG G

1 1 4 1 2 8 1 2 5 7 1 2 3 6 7

1 2

++ + + ++

(D) G G G G G G G G G G G G G G GG G

1 1 2 3 6 7 1 3 4 5 1 2 3 6 7 8

1 2

+ + + ++

Q.9 For the signal ( )x t 2( 1) ( 1) 2( 2) ( 2) 2( 3) ( 3)t u t t u t t u t= − − − − − + − − The correct waveform is

Q.10 The function Z1 is(A) a b c+ + (B) ab ac bc+ +

(C) a b c7 7 (D) a b c5 5

Q.11 If (211) (152)x 8= , then the value of base x is(A) 6 (B) 5

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(C) 7 (D) 9

Q.12 For the circuit shown below the input voltage vi is as shown in figure.

Assume the RC large and cutin voltage of diode 0V =γ . The output voltage vo is

Q.13 An ideal pn junction diode is operating in the forward basic region. The change in diode voltage, that will cause a factor of 9 increase in current, is(A) 83 mV (B) 59 mV

(C) 43 mV (D) 31 mV

Q.14 If the base width of a bi-polar transistor is increased by a factor of three then what is the collector current change ?(A) Increased by a factor of three (B) Decreased by a factor of three

(C) Neither increased nor decreased

(D) Collector current is independent of base width

Q.15 For a n -channel enhancement-mode MOSFET the parameters are 0.8 VVTN = , 8 /A Vk '

n2μ= and / 5W L = . If the transistor is biased in saturation region with

0.5 mAID = , then required vGB is(A) 1.68 V (B) 2.38 V

(C) 4.56 V (D) 3.14 V

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Q.16 The value of the current measured by the ammeter in figure is

(A) 32 A (B) 3

5 A

(C) 65− A (D) 9

2 A

Q.17 In the given lattice network the value of RL for the maximum power transfer to it is

(A) 6.67 Ω (B) 9 Ω

(C) 6.52 Ω (D) 8 Ω

Q.18 In the following circuit, the switch S is closed at 0t = . The rate of change of current

(0 )dtdi + is given by

(A) 0 (B) LR Is s

(C) ( )

LR R Is s+

(D) 3

Q.19 Let .

/A mJ u u250 0120

xz2

2

ρ ρ ρ= −

+ρ . The value of tv

22ρ is

(A) 7.8 /A m2 (B) 4.6 /A m2−

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(C) 4.6 /A m2 (D) 0

Q.20 A vector field is E 4 2 2 2sin sinzy y x y xu u ux y z2 2= + + The surfa ce on which 0Ey = is

(A) Plane 0y = (B) Plane 0x =

(C) Plane 3x 2π= (D) all

Q.21 In a nonmagnetic medium , 5 (10 8 ) 4 (10 8 )cos sint x t xE u ux z9 9= − + − V/m. The

dielectric constant of the medium is(A) 3.39 (B) 1.84

(C) 5.76 (D) 2.4

Q.22 The aerial current of an AM transmitter is 18 A when unmodulated but increases to 20 A when modulated. The modulation index is(A) 0.68 (B) 0.73

(C) 0.89 (D) None of the above

Q.23 A carrier is phase modulated (PM) with frequency deviation of 10 kHz by a signal tone frequency of 1 kHz. If the signal tone frequency is increased to 2 kHz, assuming that phase deviation remains unchanged, the bandwidth of the PM signal is(A) 21 kHz (B) 22 kHz

(C) 42 kHz (D) 44 kHz

Q.24 A die is thrown thrice. Getting 1 or 6 is taken as a success. The mean of the number of successes is(A) 3/2 (B) 2/3

(C) 1 (D) None

Q.25 Let ( )f x ex= in [0,1]. Then, the value of c of the mean-value theorem is(A) 0.5 (B) ( 1)e −(C) ( 1)log e − (D) None

Q.26- Q.55 carry two mark each.

Q.26 For /dy dx xy= given that 1y = at 0x = . Using Euler method taking the step size 0.1, the y at 0.4x = is

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(A) 1.0611 (B) 2.4680

(C) 1.6321 (D) 2.4189

Q.27 The solution of 0tan secdxdy y x y x2− − = is

(A) sin cosy x c x11= +− (B) sin cosy x c x1

2=− +−

(C) cos siny x c x3= + (D) cos siny x c x14=− +−

Q.28 e dxdydzx y z

0

1

0

1

0

1 + +### is equal to

(A) ( 1)e 3− (B) ( 1)e23 −

(C) ( 1)e 2− (D) None of these

Q.29 A lossless transmission line with a characteristic impedance of 80 Ω is terminated by a load of 125 Ω. The length of line is 1.25λ. The input impedance is(A) 80 Ω (B) 51.2 Ω

(C) 125 Ω (D) 45 Ω

Q.30 In a nonmagnetic medium ( 6.25)rε = the magnetic field of an EM wave is 6 (10 )cos cosx tH uz

8β= A/m. The corresponding electric field is(A) 903 (0.83 ) (10 )sin sin ux t y

8 V/m

(B) 903 (1.2 ) (10 )sin sin ux t y8 V/m

(C) 903 (0.83 ) (10 )sin cos ux t y8 V/m

(D) 903 (1.2 ) (10 )sin cos ux t y8 V/m

Q.31 The plane 2 3 4 1x y z+ − = separates two regions. Let 2r1μ = in region 1 defined by 2 3 4 1x y z >+ − , while 5r2μ = in region 2 where 2 3 4 1x y z <+ − . In region

50 30 20H u u ux y z1 = − + A/m. In region 2,H2 will be(A) 63.4 43.18 19.4u u ux y z+ + A/m (B) 52.9 25.66 1 .u u u4 2x y z− + A/m

(C) 48.6 16.4 46.3u u ux y z− − A/m (D) None of the above

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Q.32 A total of 30 equal-power users are to share a common communication channel by CDM. Each user transmit information at a rate of 10 kbps via DS spread spectrum and binary PSK. The minimum chip rate to obtain a bit error probability of 10 5−

(A) 1.3 106# chips/sec (B) 2.9 105

# chips/sec

(C) 1.9 106# chips/sec (D) 1.3 105

# chips/sec

Q.33 The channel capacity of the binary symmetric channel shown below is

(A) log logq q p p2 2+ (B) 1 log logp p q q2 2− −

(C) log logq q p p2 2− + (D) 1 log logq q p p2 2+ +

Q.34 It was found that a sampling rate 20% above the rate Would be adequate. So the maximum SNR, that can be realized without increasing the transmission bandwidth, would be(A) 64.4 dB (B) 70.3 dB

(C) 50.1 dB (D) None of the above

Q.35 A superheterodyne FM receiver operates in the frequency range of 88-108 MHz. The IF and local oscillator frequency are chosen such that f f<IF LO . The infe frequency must fall outside of the 88-108 MHz region. The range of variation in fLO is(A) [98,128] MHz (B) [78,128] MHz

(C) [98,118] MHz (D) [78,98] MHz

Q.36 A state-space representation of a system is given by

0x x02

1= −

o > H , [ ]y x1 1= − , and (0)x01= > H

The time response of this system will be

(A) sin t2 (B) sin t2

3 2

(C) sin t2

1 2− (D) sin t3 2

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Q.37 Consider a ufb system whose open-loop transfer function ( )( )

G ss s s

K2 22=

+ +. The

Nyquist plot for this system is

Q.38 Consider the system shown below.

The sensitivity of the steady state error to parameter α to step input is

(A) 1α

α − (B) 12α

α −

(C) 12

αα− (D) 1α

α−

Q.39 Suppose we have given following information about a signal ( )x t :1. ( )x t is real and odd.

2. ( )x t is periodic with 2T =

3. Fourier coefficients [ ] 0X k = for 1k >

4. ( )x t dt21 2

0

2# 1=

The signal, that satisfy these condition, is

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(A) sin t2 π and unique (B) sin t2 π but not unique

(C) 2 sin tπ and unique (D) 2 sin tπ but not unique

Q.40 If the input to this system is ( ) (2 )cosx t tπ θ= + , then output will be

(A) (2 )sin t32 π θ− + (B) 3 (2 )sin t2

π π θ+

(C) 2 (2 )sin t3π π θ+ (D) None of the above

Q.41 Two causal finite length sequences are given following. { [ ]}y n {6,11, 13,16,1,9,2,8}= − and { [ ]}h n {2,5, 1,4}= −

If [ ] [ ] [ ]y n h n x n= * , then sequence [ ]x n is(A) { 2,0,1,2}− (B) {3, 2,0,1,2}−

(C) {6,2,5, 1,4}− (D) {6,11, 13,16,1}−

Q.42 Consider the following 8085 assembly program MVI A, DATA1 MOV B, A SUI 51H JC DLT MOV A, B SUI 82H JC DSPLYDLT : XRA A OUT PORT1 HLTDSPLY : MOV A, B OUT PORT2 HLTThis program will display(A) the bytes from 51H to 82H at PORT2

(B) 00H AT PORT1

(C) all byte at PORT1

(D) the bytes from 52H to 81H at PORT 2

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Q.43 The frequency of oscillation of the astable multivibrator shown below is

(A) 18.4 kHz (B) 9.86 kHz

(C) 98.6 kHz (D) 1.84 kHz

Q.44 The counter shown in figure below is a

(A) MOD-8 up counter (B) MOD-8 down counter

(C) MOD-6 up counter (D) MOD-6 down counter

Q.45 The circuit shown below has 4 boxes each described by input , ,P Q R and output ,Y Z with Y P Q R5 5= and Z PQ PR QR= + + .

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The circuit act as a 4 bit(A) adder giving P Q+ (B) subtractor giving P Q−

(C) subtractor giving Q P− (D) adder giving P Q R+ +

Q.46 Consider the ideal op-amp circuit shown below

If it is given that RR

1

2 10= , 11RR

3

4 = . The common mode rejection ratio (CMRR) is(A) 20.8 dB (B) 47.6 dB

(C) 41.6 dB (D) 23.8 dB

Q.47 In the circuit shown below the Q -point is in the center of the load line. The transistor parameters are 150β = and VA 3= .

The small-signal voltage gain A vv

vs

o= is

(A) 16.43− (B) 9.438−

(C) 5.75− (D) 3.94−

Common Data for Q. 48-49 :

Q.48 A 2.4 cm # 1.5 cm wave guide operates in TE10 mode at 9 GHz. The guide is made of brass ( 1.1 10c

7σ #= S/m) and filled with teflon ( 2.6, 10r d15ε σ= = − S/m).

The attenuation constant, due to conduction losses, cα is

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(A) 0.0395 (B) 0.022

(C) 0.0145 (D) 0.0193

Q.49 The attenuation constant due to dielectric losses is(A) 5.9 10 12

#− Np/m (B) 1.3 10 13

#− Np/m

(C) 2.4 10 11#

− Np/m (D) None of the above

Common Data for Q 50-51 :Consider the system shown below .The average value of ( )m t is zero and maximum value of ( )m t is M . The square-law device is defined by ( ) 4 ( ) 10 ( )y t x t x t= + .

Q.50 The value of M , required to produce modulation index of 0.8, is(A) 0.32 (B) 0.26

(C) 0.52 (D) 0.16

Q.51 Let W be the bandwidth of message signal ( )m t . AM signal would be recovered if(A) f W>c (B) 2f W>c

(C) 3f W>c (D) 4f W>c

Statement for Linked Answer Q. 52-53:

Q.52 In n -type silicon MOS structure a metal-semiconductor work function difference of 0.35msΦ =− V is required. If gate is n+ polysilicon the required silicon doping required is(A) 4 10 cm11 3

#− (B) 4 10 cm13 3

#−

(C) 4 10 cm16 3#

− (D) Cannot use n+ polysilicon gate

Q.53 If gate is p+ polysilicon, then the required silicon doping is(A) 8 10 cm11 3

#− (B) 8 10 cm13 3

#−

(C) 8 10 cm15 3#

− (D) Cannot use n+ polysilicon gate

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Statement for Linked Answer Q. 54-55 :For the p-channel transistor in the circuit shown below the parameters are 6IDSS = mA, 4 VVP = and 0λ = .

Q.54 The value of IDQ is(A) 8.86 mA (B) 6.39 mA

(C) 4.32 mA (D) 1.81 mA

Q.55 The value of VSD is(A) 4.28− V (B) 2.47 V

(C) 4.28 V (D) 2.19 V

General Aptitude (GA) Questions

Q. 56-Q. 60 carry one mark each.

Q.56 Which of the following word in the options is closest in meaning to the word given below ?FLIPPANT(A) Obverse (B) Irreverent

(C) Feeble (D) Candid

Q.57 The question below consists of a pair of related words followed by four pairs of words. Choose the pair which best expresses the relation in the original pair.Doctor : Healing(A) PRISON : GUARD

(B) DINOSAURS : PALEONTOLOGIST

(C) AUTHOR : WRITING

(D) PLANETS : UNIVERSE

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Q.58 Choose the most appropriate words from the options given below to fill the blanks in the given sentences.It is evident from the...... 9/11, that followed the occupation of Iraq, the the terrorist’s anger is the result of cultural ............., often combined with direct personal degradation.(A) war, discrimination (B) violence, vendetta

(C) carnage, humiliation (D) aftermath, bigotry

Q.59 In the following series, choose the odd one out84129, 32418, 47632, 36119, 67626, 72927

(A) 84129 (B) 32418

(C) 47632 (D) 72927

Q.60 Salma’s current age is 24 years grater than her son Danish’s age. In 8 year, Salma’s age will be twice Danish’s age at that time. What is Salma’s current age ?(A) 32 (B) 40

(C) 48 (D) 52

Q. 61-Q. 65 carry two mark each.

Q.61 People who discontinue regular exercise claim that exercising amounted to wasted time for them. But this calm is born of laziness, in light of the over-whelming evidence that regular exercise improves one’s health.Which of the following statements, if true, would most seriously weaken the argument above ?(A) Exercise has been shown to not only improve one’s health, but also to increase

longevity, or life span.

(B) People who have discontinued regular exercise now make productive use of the time they formerly devoted to exercise.

(C) People who are in good health are more likely to exercise regularly than people who are in poor health.

(D) A person need not exercise every day to experience improved health from the exercise.

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Q.62 If anda b are negative integers, and if 1a b− = , what is the least possible value of ab ?(A) 0 (B) 1

(C) 2 (D) 3

Statement for Q. 63-64 :In the following graph area of warehouse units A, B, C and D as portions of total warehouse are shown

Q.63 By approximately how much many square feet does the size of Unit A exceed that of unit C ?(A) 9000 (B) 11000

(C) 12500 (D) 15500

Q.64 The combined area of Unit B and Unit D is approximately(A) 51000 square feet (B) 57500 square feet

(C) 70000 square feet (D) 74500 square feet

Q.65 P can do a piece of work in 12 days and Q can do the same work in 18 days. If P works for three days, then in how many days will the remaining work be completed by Q ?(A) 13.5 days (B) 9 days

(C) 16.5 days (D) 12 days

END OF THE QUESTION PAPER

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ATTENTION!

For Detailed Solutions Please Mail to [email protected] with Subject MOCK Test Solutions and provide following details in your email• Name:• College:• City:• Mode of Preparation: Coaching/self study• Phone no:• How have you heard about GATHELP? ....• Are you referring any book by NODIA for your GATE Preparation: Yes/No

(If Yes, Mention Books)

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