Mock GATE Exam - 2019 - Electrical Engineering

1. What will be the maximum sum of 44, 42, 40, ...... ?

500

502

504

506

Submit

3. The product of two complex numbers 1 + i and 2 - 5i is

7 - 3i

3 - 4i

- 3 - 4i

7 + 3i

4. Four red balls, four green balls and four blue balls are put in a box. Three balls are pulled out of the box at random one after another without replacement. The probability that all the three balls are red is

1/72

1/55

1/36

1/27

Submit

6. The Maxwell's bridge shown in the figure is at balance. The parameters of the inductive coil are

R =R2R3 / R4, L = C4R2R3

L =R2R3 / R4, R = C4R2R3

R =R4 / R2R3, L = 1/(C4R2R3)

L =R4 / R2R3, R = 1/(C4R2R3)

Submit

8. A 0-1 Ampere moving iron ammeter has an internal resistance of 50mΩ and inductance of 0.1 mH. A shunt coil is connected to extend its range to 0-10 Ampere for all operating frequencies. The time constant in milliseconds and resistance in mΩ of the shunt coil respectively are

1,2

5.55,2

2, 5.55

2,1

Submit

11. The Octal equivalent of HEX and number AB.CD is

253.314

253.632

526.314

526.632

12. A separately excited DC motor runs at 1000 rpm on no load when its armature terminals are connected to a 200V DC source and the rated voltage is applied to the field winding. The armature resistance of this motor is 1Ω. The no-load armature current is negligible. With the motor developing its full load torque, the armature voltage is set so that the rotor speed is 500 rpm. When the load torque is reduced to 50% of the full load value under the same armature voltage conditions, the speed rises to 520 rpm. Neglecting the rotational losses, the full load armature current (in Ampere) is _____

Submit

13. The inverse Laplace transform of 1/(s^2+s) is

1+et

1+e-t

1-e-t

None

14. What is the adverb for the given word below? Misogynous

Misogyousness

Misogynity

Misogynously

Misogynous

15. The function y = |2 - 3x|

Is continuous ∀x ∈ R and differentiable ∀x ∈ R

Is continuous ∀x ∈ R and differentiable ∀x ∈ R except at x = 3/2

Is continuous ∀x ∈ R and differentiable ∀x ∈ R except at x = 2/3

Is continuous ∀x ∈ R except at x=3 and differentiable∀x ∈ R

16. In the 4m1 multiplexer, the output F is given by F=A⊕B . Find the required input ' I₃ I₂ I₁ I₀'.

1010

0110

1000

1110

17. Choose the most appropriate alternative from the options given below to complete the following sentence: Despite several ___________ the mission succeeded in its attempt to resolve the conflict.

Attempts

Setbacks

Meetings

Delegations

18. From the time the front of a train enters a platform, it takes 25 seconds for the back of the train to leave the platform, while travelling at a constant speed of 54 km/h. At the same speed, it takes 14 seconds to pass a man running at 9 km/h in the same direction as the train. What is the length of the train and that of the platform in meters, respectively?

210 and 140

162.5 and 187.5

245 and 130

175 and 200

19. A band-limited signal with a maximum frequency of 5 kHz is to be sampled. According to the sampling theorem, the sampling frequency in kHz which is not valid is

5

12

15

20

20. Torque exerted on a flywheel over a cycle is listed in the table. Flywheel energy (in J per unit cycle) using Simpson's rule is

Angle (degree)	0	60	120	180	240	300	360
Torque (Nm)	0	1066	-323	0	323	-355	0

542

993

986

None

21. The approximate transfer characteristic for the circuit shown below with an ideal operational amplifier and diode will be

22. A transporter receives the same number of orders each day. Currently, he has some pending orders (backlog) to be shipped. If he uses 7 trucks, then at the end of the 4th day he can clear all the orders. Alternatively, if he uses only 3 trucks, then all the orders are cleared at the end of the 10th day. What is the minimum number of trucks required so that there will be no pending order at the end of the 5th day?

4

5

6

7

23. If V_A-V_B=6V, then V_C-V_D is

–5V

2V

3V

6V

24. The open loop poles of a third order unity feedback system are at 0,-1,-2. Let the frequency corresponding to the point where the root locus of the system transits to unstable region be K. Now suppose we introduce a zero in the open loop transfer function at -3, while keeping all the earlier open loop poles intact. Which one of the following is TRUE about the point where the root locus of the modified system transits to unstable region?

It corresponds to a frequency greater than K

It corresponds to a frequency less than K

It corresponds to a frequency K

Root locus of modified system never transits to unstable region

25. For the network shown in the figure below, the frequency (in rad/s) at which the maximum phase lag occurs is, ___________.

0.3

0.4

0.5

0.6

26. Which of the following assertions are CORRECT? P: Adding 7 to each entry in a list adds 7 to the mean of the list Q: Adding 7 to each entry in a list adds 7 to the standard deviation of the list R: Doubling each entry in a list doubles the mean of the list S: Doubling each entry in a list leaves the standard deviation of the list unchanged

P, Q

Q, R

P, R

R, S

27.

For the circuit given above, the Thevenin's voltage across the terminals A and B is

1.25 V

0.25 V

1 V

0.5 V

28. A 4 point starter is used to start and control the speed of a

Dc shunt motor with armature resistance control

Dc shunt motor with field weakening control

Dc series motor

Dc compound motor

29. A cascade of 3 Linear Time Invariant systems is causal and unstable. From this, we conclude that

Each system in the cascade is individually causal and unstable

At least one system is unstable and at least one system is causal

At least one system is causal and all systems are unstable

The majority are unstable and the majority are causal

30. The synchronous generator shown in the figure is supplying active power to an infinite bus via two short, lossless transmission lines, and is initially in steady state. The mechanical power input to the generator and the voltage magnitude E are constant. If one line is tripped at time t₁ by opening the circuit breakers at the two ends (although there is no fault), then it is seen that the generator undergoes a stable transient. Which one of the following waveforms of the rotor angle δδ shows the transient correctly?

31. The number of accidents occurring in a plant in a month follows Poisson distribution with mean as 5.2. The probability of occurrence of less than 2 accidents in the plant during a randomly selected month is

0.029

0.034

0.039

0.044

32. A single-phase, 22 kVA, 2200 V/ 220 V, 50 Hz, distribution transformer is to be connected as an auto-transformer to get an output voltage of 2420 V. Its maximum kVA rating as an autotransformer is

24

42

242

2442

33. Nyquist plot of two functions G1(s) and G2(s) are shown in figure.

Nyquist plot of the product of G1 (s) and G2(s) is

34. The phase cross-over frequency of the transfer function G(S)=100/(S+1)^3 in rad/s is

√3

1/√3

3

3√3

35. Fact: If it rains, then the field is wet. Read the following statements: (i) It rains (ii) The field is not wet (iii) The field is wet (iv) It did not rain Which one of the options given below is NOT logically possible, based on the given fact?

If (iii), then (iv)

If (i), then (iii).

If (i), then (ii).

If (ii), then (iv).

36. After the discussion, Tom said to me, 'Please revert!'. He expects me to _________.

Retract

Get back to him

Move in reverse

Retreat

37. The integral ∮_C(ydx−xdy) is evaluated along the circle x^2+y^2=1/4 traversed in counter clockwise direction.The integral is equal to

0

π/4

−π/2

None

38. The area of a triangle formed by the tips of vectors a¯, b¯and c¯ is

0.5(a¯−b¯)⋅(a¯−c¯)

0.5 * ∣ (a¯−b¯)×(a¯−c¯) ∣

0.5 * (a¯×b¯)⋅c¯

None

39. Consider an electron, a neutron and a proton initially at rest and placed along a straight line such that the neutron is exactly at the center of the line joining the electron and proton. At t=0, the particles are release but are constrained to move along the same straight line. Which of these will collide first?

The particles will never collide

All will collide together

Proton and neutron

Electron and neutron

40. A 3-phase, 4-pole, 400 V, 50 Hz squirrel-cage induction motor is operating at a slip of 0.02. The speed of the rotor flux in mechanical rad/sec, sensed by a stationary observer, is closest to

155

156

157

158

41. A balanced (positive sequence) three-phase AC voltage source is connected to a balanced, start connected through a star-delta transformer as shown in the figure. The line-to-line voltage rating is 230 V on the star side, and 115 V on the delta side. If the magnetizing current is neglected and Is¯=100∠0° A, then what is the value of Ip¯ in Ampere?

200∠30∘

50∠30∘

Zero

None

42. In the following sequential circuit, the initial state (before the first clock pulse ) of the circuit is Q1Q0= 00. The state (Q1Q0), immediately after the 333rd clock pulse is

00

01

10

11

43. A phase-controlled, single-phase, full-bridge converter is supplying a highly inductive DC load. The converter is fed from a 230 V, 50 Hz, AC source. The fundamental frequency in Hz of the voltage ripple on the DC side is

25

50

100

200

44. A distribution feeder of 1 km length having resistance, but negligible reactance, is fed from both the ends by 400V, 50 Hz balanced sources. Both voltage sources S₁ and S₂ are in phase. The feeder supplies concentrated loads of unity power factor as shown in the figure.

The contributions of S₁ and S₂ in 100 A current supplied at location P respectively, are

75 A and 25 A

0 A and 100 A

50 A and 50 A

25 A and 75 A

45. A single-phase thyristor-bridge rectifier is fed from a 230 V, 50 Hz, single-phase AC mains. If it is delivering a constant DC current of 10 A, at firing angle of 30^o, then value of the power factor at AC mains is

0.87

0.9

0.78

Zero

46. Let x(t) be a periodic signal with time period T,Let y(t)=x(t-t₀)+x(t+t₀) for some t₀.The Fourier Series coefficients of y(t) are denoted by b_k. if b_k=0 for all odd k,then t₀ can be equal to

T/8

T/4

T/2

2T

47. The graph associated with an electrical network has 7 branches and 5 nodes. The number of independent KCL equations and the number of independent KVL equations, respectively, are

2 and 3

5 and 2

3 and 4

4 and 3

48. Given digits 2, 2, 3, 3, 4, 4, 4, 4 how many distinct 4 digit numbers greater than 3000 can be formed?

50

51

52

53

49. A zero mean random signal is uniformly distributed between limits −a and +a and its mean square value is equal to its variance. Then the r.m.s value of the signal is

A/√3

A/√2

A√3

None

50. The direction of rotation of a single-phase capacitor run induction motor is reversed by

Interchanging the terminals of the AC supply.

Interchanging the terminals of the capacitor

Interchanging the terminals of the auxiliary winding

Interchanging the terminals of both the windings.

51. The figure shows the power per-phase representation of a phase-shifting transformer connected between buses 1 and 2, where αα is a complex number with non-zero real and imaginary parts.

For the given circuit, Y_bus and Z_bus are bus admittance matrix and bus impedance matrix, respectively, each of size 2 m 2. Which one of the following statements is true?

Both Ybus and Zbus are symmetric

Ybus is symmetric and Zbus is unsymmetric

Ybus is unsymmetric and Zbus is symmetric

Both Ybus and Zbus are unsymmetric

52. Given that the op-amps in the figure are ideal, the output voltage V₀ is

(V1-V2)

2(V1-V2)

2(V1-V2)/2

(V1+V2)

53. A 3-phase voltage source inverter is supplied from a 600 V DC source as shown in the figure below. For a star connected resistive load of 220 Ω per phase, the load power for 120° device conduction in kW, is____________.

7

8

9

10

54. A three phase synchronous generator is to be connected to the infinite bus. The lamps are connected as shown in the figure for the synchronization. The phase sequence of bus voltage is R-Y-B and that of incoming generator voltage is R'-Y'-B'.

It was found that the lamps are becoming dark in the sequence L_a-L_b-L_c. It means that the phase sequence of incoming generator is

Same as infinite bus and its frequency is more than infinite bus

Opposite to infinite bus but its frequency is less than infinite bus

Opposite to infinite bus and its frequency is more than infinite bus

Same as infinite bus and its frequency is less than infinite bus

55. Determine the correctness or otherwise of the following Assertion [a] and the Reason [r]. Assertion: Fast decoupled load flow method gives approximate load flow solution because it uses several assumptions. Reason: Accuracy depends on the power mismatch vector tolerance.

Both [a] and [r] are true and [r] is the correct reason for [a].

Both [a] and [r] are true and [r] is not the correct reason for [a]

Both [a] and [r] are false.

[a] is false and [r] is true

56. Choose the most appropriate word from the options given below to complete the following sentence: His rather casual remarks on politics______his black of seriousness about the subject.

Masked

Belied

Betrayed

Suppressed

Submit

58. The positive, negative and zero sequence impedances of a 125 MVA, three-phase, 15.5 kV, star-grounded, 50 Hz generator are j0.1 pu, j0.05 pu and j0.01 pu respectively on the machine rating base. The machine is unloaded and working at the rated terminal voltage. If the grounding impedance of the generator is j0.01 pu, then the magnitude of fault current for a b-phase to ground fault (in kA) is _____ (up to 2 decimal places).

Submit

65. A dc to dc converter shown in the figure is charging a battery bank, B2 whose voltage is constant at 150 V. B1 is another battery bank whose voltage is constant at 50 V. The value of the inductor, L is 5 mH and the ideal switch, S is operated with a switching frequency of 5 kHz with a duty ratio of 0.4. Once the circuit has attained steady state and assuming the diode D to be ideal, the power transferred from B1 to B2 (in Watt) is

10

12

14

24