gate electrical questions

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Q. No. 1 25 Carry One Mark Each

1. A card is drawn at random from a pack of cards, if it is known that the card drawn is red,

what is the probability that it is a heart?

(A) 0.87 (B) 0.75 (C) 0.5 (D) 0.59

2. The system of equations 5x 2y 3z 0, 2x 5y 3z 0, 2x 3y 5z 0 is

(A) homogeneous and admits no solutions

(B) homogeneous and admits infinite solutions

(C) homogeneous and admits only trivial solutions

(D) None of these

3. If z=3+i then (z 1)(z 1)

(A) 17 (B) -17 (C) 17 (D) 17

4. The function 3 2f x x ax bx c, 2a 3b has

(A) one maximum value (B) one minimum value

(C) no extremum value (D) one maximum & one minimum

5. If 2

t 1 if t 1f t

0 if 0 t 1

then value of L[f(t)] is

(A) s

3

2e

s

(B) s

3

e

s

(C) s

2

3e

s

(D) s

2

2e

s

6. When a and b are shorted in the following network, current flowing from a to b will be

(A) 1A

(B) 2A

(C) 3A

(D) 7A

2A

18V4 6

3A

10 V

5

ab



7. It is given that series voltage s12V for t 0s

V t0V for t 0s

The value of CV at t 0s is

(A) 0 V (B) 6 V (C) 12 V (D) 18 V

8. If a 4-pole 50Hz three phase induction motor rotating at 1440 r.p.m , has a standstill reactance

of 3.5 per phase, then the running reactance will be _________.

9. In a synchronous machine, the field winding is on stator and armature winding is on rotor,

when running under synchronous speed, its armature field is

(1) stationary w.r.t rotor

(2) stationary w.r.t stator

(3) rotating at double the synchronous speed (NS) w.r.t stator in opposite direction.

(4) rotating at synchronous speed (NS) w.r.t stator

(5) stationary w.r.t stator field rotation

(A) 2 & 3 (B) 1, 3 & 5 (C) 2, 3 & 5 (D) 1, 2, 3 & 4

10. Determine the phase sequence in the slots for a 3 , 2 pole, 12-slot alternator with 2

slots/pole/phase, for a single layer winding with 60O phase spread.

(A) RB RB YY R R BBYY (B) RR-B- B YYRR BBY-Y

(C) RBY (D) None of these

11. Consider a power system with three identical generators. The transmission losses are

negligible. One generator (G1) has a speed governor which maintains its speed constant at the

rated value, while the other generators (G2&G3) have governors with a drop of 5%. If the load

of the system is increased, then in steady state

(A) generation of G2 & G3 is increased equally while generation of G1 is unchanged.

(B) generation of G1 is increased while generation of G2 & G3 is unchanged.

(C) generation of G1, G2 & G3 is increased equally.

(D) generation of G1, G2 & G3 is increased in the ratio 0.5 :0.25:0.25

41

2V

SV

CV4

1V

i

1F

24



12. Consider the following circuit

If 0V 10.3V , then Zener voltage is ___________V.

13. For the transistor shown in figure, determine the operating point.

(A) (5.4V, 3.3mA) (B) (6.4V, 4.3mA)

(C) (7.4V, 5.3mA) (D) (8.4V, 6.3mA)

14. A 50 Hz, 11 kV, three phase synchronous generator has an inductance per phase of 1.75 mH

and its neutral is grounded. It feeds a line through a circuit breaker. The total stray

capacitance to ground of the generator and circuit breaker is 0.0025 F . A fault occurs just

beyond the circuit breaker, then the time at which peak restricting voltage occurs is

___________ s .

15. Which of the following condition must be used for avoiding local hot spots in SCR?

(A) Applying a reverse voltage across SCR

(B) Applying anode current below holding current

(C) Using low dI

dt value

(D) Applying higher gate current during turn on time

+12V

IC

1 K 4K

8K 1K

IB

ZV

V

V0V

iR 1k

iE 5V



16.

The k-map of a 3 variable Boolean function F is given. Its minimized expression is

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

17. Match List I & List II.

LIST-I LIST-II

P. y n 2y n 1 4x n 1. Linear & time varying

Q. y n 2ny n 1 x n 2. Non Linear & time varying

R. 2y n 2y n 1 2x n 3. Non Linear & time invariance

S. y n 4y n y 2n x n 4. Linear & time invariance

(A) (P-1), (Q-2), (R-3), (S-4) (B) (P-1), (Q-2), (R-4), (S-3)

(C) (P-4), (Q-1), (R-3), (S-2) (D) (P-4), (Q-3), (R-1), (S-2)

18. The over modulation of Sine-PWM inverter is generally avoided because it introduces

(A) Lower frequency harmonics in the inverter output waveform

(B) Nonlinearity between the magnitude of modulating signal and fundamental output voltage of the inverter

(C) Both (A) & (B)

(D) None of these

19. Evaluate the value of t(5t e ) '(t)dt

(A) 6 (B) -6 (C) 4 (D) -4

20. Calculate the resistance at the terminals a & b.

(A) 4 (B) 2 (C) 1 (D) 3

00 01 10 11

0 1 0 0 1

1 1 0 0 1

A

BC

2

2 x

1.5V

a

b

xV

Rab



21. Calculate 1R & R in the circuit shown below.

(A) 1R 0 ; R

(B) 1R 2 ; R 1

(C) 1R 1 ; R 2

(D) 1R 2 ; R 2

22. Which type of control mechanism is used in power factor meter?

(A) Spring control mechanism (B) Gravity control mechanism

(C) Either (A) or (B) (D) Not required controlling

23. For generating circle on the CRO screen, which of the following statements are TRUE?

(i) Both horizontal and vertical plates are applied through sinusoidal signal with phase

displacement of 900

(ii) Horizontal plates are applied through sweep signal and vertical plates are applied through

sinusoidal signal with phase displacement of 900

(iii) Horizontal and vertical plates are applied through sinusoidal signal with phase

displacement of 2700

(A) Only (i) (B) Only (ii) (C) Both (i) & (ii) (D) Both (i) & (iii)

24. Current flowing through the inductance of 2H is shown in the figure below.

Calculate x, if the energy stored by the inductor up to 8sec is 36J.

(A) 4A (B) 8A (C) 6A (D) 10A

25. If the E and H fields of a time periodic wave in free space are

7 70 x y E E cos 10 t z a V / m and H 5cos 10 t z a A / m , then the constant E0 is

(A) 600 (B) 600 (C) 240 (D) 720

Q. No. 26 55 Carry Two Marks Each

26. The orthogonal trajectory of cardioid r a 1 cos (a is parameter ) is

(A) r kccos (B) r kc tsin

(C) r k 1 cos

(D) r kc t cos

i(t)

2 4 5 8

9

2A

x

t(sec)

1 1 1R

1

0.5A

4V

2A

R 2



27. The error in the estimation of 0

cos d

using trapezoidal rule with three equal intervals of

width 3

, is ____________.

28. The directional derivative of 2 2x yz 4xz at 1, 2, 1 in the direction of 2i j-k is

(A) 9

3 (B)

9 3

2 (C)

9

2 (D)

37

3

29. The value of b by fitting a line y = a + bx for the given data by method of least squares is _________.

(A) 0 (B) 2 (C) 1 (D) 1

30. The value of R, for which it absorbs maximum power is

(A) 4

(B) 3

(C) 2

(D) None of the above

31. Transfer function of a unity negative feedback system is given as 2

1T

s s 1

. Determine

the ratio of percentage change in T to the percentage change in G (where G is the open loop

transfer function)

(A)

2

s s 1

s s 1

(B)

2

s 1

s s 1

(C)

2

s s 1

s s 1

(D)

2

s 1

s s 1

32. The impedance parameters for the network

(A) 1 0

0 1

(B) 1 1

0 1

(C) 0 1

1 0

(D) 1 1

1 1

x 1 2 3 4

y 2 1 0 1

E 4 A24 R

4 2 2

Ri

A

B

bZ 1

aZ 1

bZ 1

aZ 1

C D

1I



33. The forward path and feedback path gains of a unity negative feedback system are given

below

K(s 8) (s 10)

G(s) , H(s)(s 6)(s 2) (s 4)

The value of K for which s = -12 will a closed loop pole for the system is ___________.

34. The synchronizing reactance of an isolated synchronous machine is10 . When the reactance

of the machine decreases, then what happens to the stability and air gap length if armature

reaction is neglected?

(A) Stability decreases and air gap length decreases

(B) Both stability and air gap length increases

(C) Stability increases and air gap length decreases

(D) Stability decreases and air gap length increases

35. In a synchronous generator, Xd=1pu, Xq=0.7pu, O30 and E=1.2pu. The percentage of

power developed due to saliency is __________.

36. The ohmic loss at full load for the 33kVA transformer shown below is __________kW.

37. The transistor shunt regulator shown in figure has a regulated output voltage of 10V, where

the input varies from 20V to 30V. The relevant parameters for the zener diode and the

transistor are Vz = 9.5V, VBE = 0.3V, = 99. Neglect the current through RB.

Determine the maximum dissipated power in the zener diode (Pz).

V0 = 10V

I1

IZ IC

+ VBE

- RB

Vin=20-30V

R 20

3

4

2I

4

5

1I

1R

1x

2x

1V

cR

mx

2V

2 2

1 1

V N 220

V N 2200



(A) 75mW (B) 85mW (C) 95mW (D) 115mW

38. A source follower has gain Av = 0.95. The FET parameters are =40 and rd=40k. Find the values of Rs and output impedance.

(A) 36.19 k, 36.19 k (B) 6.75 k, 379

(C) 36.18 k, 976 (D) 975 , 975

39. A DC generator is having commutator with diameter of 10cm, rotating at speed of 500rpm,

brush width is 1.2cm and self-inductance of coil is 1mH. Determine the reactance voltage.

(A) 0.9609V

(B) 0.873V

(C) 0.736V

(D) None of these

40. All the logic gates used in the following logic circuit are from TTL family. The output

expression Y is

(A) AB (B) AB.C (C) AB C (D) Cant say

41. If 5 Y(123) (X8) then the minimum value of Y that satisfy the given equation is _______.

42. A memory interfacing circuit is given in below figure. The mirror (foldback) address range of

the memory chip for the given decoding circuit is

(A) 0000H-1FFFH

(B) 3FFFH-FFFFH

(C) 0000H-2000H

(D) 2000H-3FFFH

15A

14A

G

B

A

2 to 4

Decoder

3Y

2Y

1Y

0Y

IO M12A

0A

RD

7D 0D

8k 8

EPROM

CE

A

B

C

Y

Floating Input

2A

200V



43. A three phase 4 pole induction motor has a full load slip of 2%. The rotor resistance and

standstill reactance per phase are 0.001 and 0.005 respectively. The ratio of full load torque to the maximum torque is __________.

44. The Fourier transform of shown function is

(A) j 2 j1

1 e 2ej

(B) j 2 j

11 e 2e

j

(C) j 2 j1

1 e 2ej

(D) j 2 j1 e 2e

45. A synchronous generator is connected to a 11 kV infinite bus through a transmission line. The

reactances of the generator and transmission lines are 1.2 and 0.8 respectively. Assume

E=15kV for synchronous generator. If the generator delivers 70 MW power to the infinite

bus, then the load angle ( ) is ___________degrees.

46. A system has a quadratic pole (complex conjugate pole) depicted in Bodes plot shown. Determine the steady state error generated when subjected to a unit step input.

(A) 1

10 (B)

1

11 (C)

1

20 (D)

1

21

47. A system with free forced response

1

4 s is subjected to a sinusoid sin (3t). The steady

state response y (t) will be

(A) o1

sin(3t 37 )5

(B) o1

sin(3t 37 )5

x(t)1

2

0 1 2

t

20dB0.5

40dB / decade

rad / sec

G(j ) dB



(C) o1

cos(3t 37 )5

(D) o1

cos(3t 37 )5

48. The open loop transfer function of a system is

1

G(s)H(s)(1 s)(1 2s)(1 3s)(3 2s)

A PD controller with constants Kp and Kd is introduced such that steady state error for a unit

step input signal is 0.5 and has a phase crossover frequency of 1rad / sec , then the values of

Kp and Kd are respectively

(A) 2, 3 (B) 4, 6 (C) 6, 4 (D) 3, 2

49. A three phase 33kV line feeds a per phase load of 10 MW. If the impedance of the line is

z j20 , then the value of load angle to maintain line voltage of 33kV at a load is

(A) 33.44o (B) 10.6

o (C) 30

o (D) 60

o

50. Which of the following PWM schemes can produce a good quality line voltage (free from

voltage harmonics) of 95V (RMS) and 50Hz for a DC link voltage of 142V?

(A) Sine PWM (B) Sine + Third harmonic PWM

(C) Space vector PWM (D) Both (B) & (C)

51. What should be the starting value of current to SCRs shown below, if each has rated for 100A?

(A) T T T T1 2 3 4I 200A I 0A I 110A I 90A

(B) T T T T1 2 3 4I 200A I 0A I 200A I 100A

(C) T T T T1 2 3 4I 200A I 0A I 100A I 200A

(D) T T T T1 2 3 4I 200A I 0A I 100A I 100A

52. TypeA chopper circuit supplies power to a battery with its terminal voltage of 160V. The output voltage of the chopper consists of rectangular pulses of 4 ms duration in a cycle of

overall time 10 ms. The rms value of the fundamental component of output voltage,

neglecting internal resistance of the battery is _________V.

70 s, 60C

200A

2TT2

I

20 s, 60C

1TT1I

200A

10 s, 60C

T3I

20 s, 60C

T4I4T3

T



53. A lissajous pattern on CRO screen is stationary and it has 4 horizontal tangencies and 3

vertical tangencies. The frequency of vertical input is 1.5kHz, then the frequency of

horizontal input is __________kHz.

54. The vector 4 5 5 4 3x y z V x y a x y a z a is

(A) Solenoidal (B) Irrotational (C) Both (A) and (B) (D) None of these

55. A wattmeter has a current coil of 0.03 resistance and a pressure coil of 6000 resistance.

The load takes 20A at a voltage of 220V and a 0.6 power factor. The load current (in A)

which give equal error with the two connections is ___________.

Q. No. 56 60 Carry One Mark Each

56. A dishonest dealer professes to sell his article at cost price but he uses a false weight with

which he cheats 30% while buying and 20% while selling. Find his profit percentage in the

transaction.

(A) 50% (B) 62.5% (C) 41.67% (D) 43.33%

57. Choose the word from the options given below that is most nearly in meaning to the given

word:

MORIBUND

(A) lively (B) commotion (C) stagnant (D) dejected

58. Choose the word from the options given below that is most nearly opposite in meaning to the

given word:

RECALCITRANT

(A) refractory (B) repulsive (C) obedient (D) considerable

59. Choose the most appropriate word from the options given below to complete the following

sentence:

Autumn 2003 marked the start of the 50th anniversary . of Dylan Thomas ' untimely death.

(A) celebration (B) congress (C) commemorations (D) proceedings

60. Directions for the Question 65: Considering the statements a, b and c to be true, choose the

conclusions which are definitely true from the statements disregarding commonly known

facts.

(a) All Ts are Ss

(b) All Ss are Rs

(C) All Rs are Us

Conclusions:



(i) Some Us are Ts (ii) Some Us are Ss (iii) Some Rs are Ss

(A) Only (ii) follows (B) Only (i) & (ii) follows

(C) All follows (D) None follows

Q. No. 61 65 Carry Two Marks Each

61. Two explosions took place at a time interval of 60 minutes at same location. A biker moving

away from the place heard the first explosion when he was at place X and heard the next

explosion at a place Y after 63 minutes. What is the distance between the two places X and Y,

if the speed of sound was 267 m/s?

(A) 27.9 Km (B) 48.6 Km (C) 48.06 Km (D) 52.06 Km

62. What could be the maximum number of distinct divisions a plane can be divided using 101

lines?

(A) 202 (B) 203 (C) 5151 (D) 5152

63. Information for Question:

Study the following graph and answer the question given below it

What is the ratio of number of years in which the actual production was above the average

production to the number of years whose actual production is below the average production?

(A) 2 : 1 (B) 1 : 1 (C) 1 : 2 (D) 3 : 2

400

300

200

100

0

225

175

75

185

1996-97 1997-98

(in

th

ou

san

d b

ags)

Target

Actual

200

150 95

250

175

225

300 325

(in thousand bags)

1998-99 1999-00 2000-01 2001-02

years



64. Two containers contain wine and water in the ratio 7:6 and 7:2 respectively. What quantity

(approximately) from the first container should be mixed with 714.42 litres of the second

such that the new mixture contains wine and water in the ratio 7:3?

(A) 714 litres (B) 388 litres (C) 398 litres (D) 344 litres

65. Select the best alternative out of the given options:

(A) In addition of enhancing their reputation through strategic use of high profit funds for

customers, companies are sponsoring social initiatives to open new markets.

(B) In addition to having enhance their reputation through strategic use of high profit funds

for customers, companies are sponsoring social initiatives to open new markets.

(C) In addition to enhancing their reputation through strategic use of high profit funds for


(D) In addition of enhancing their reputations through strategic use of high profit funds for


gate electrical questions

Documents

b generation of g1

maximum value b

c generation of g1

solutions b homogeneous

d generation of g1

t rotor

minimum value c

b yyrr bbyy c rby d