GATE 2013 ELECTRICAL ENGINEERING PAPER SET-B THEORY QUESTIONS

4. A bulb in a staircase has two switches, one switch being at the ground floor and the other at the first floor. The bulb can be turned ON and also be turned OFF by any one of the switches irrespective of the state of the other switch. The logic of switching of the bulb resembles

a) an AND gate

b) an OR gate

c) an XOR gate

d) a NAND gate

5. For periodic signal v(t)= 30 sin 100t+ 10cos 300t+ 6 sin(500t+π/4), the fundamental frequency in rad/s is

a) 100

b) 300

c) 500 

d) 1500

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

a) 5

b) 12

c) 15

d) 20

8. The angle δ in the swing equation of a synchronous generator is the 

a) angle between stator voltage and current.

b) angular displacement of the rotor with respect to the stator.

c) angular displacement of the stator mmf with respect to a synchronously rotating axis.

d) angular displacement of an axis fixed to the rotor with respect to a synchronously rotating axis.

9. Leakage flux in an induction motor is

a) flux that leaks through the machine.

b) flux that links both stator and rotor windings.

c) flux that links none of the windings.

d) flux that links the stator windings or the rotor winding but not both.

18. Which one of the following statements is NOT TRUE for a contiunous time casual and stable LTI system?

a) All the poles of the system must lie on the left side of the jw axis.

b) zeros of the system can lie anywhere in the s-plane.

c) all the poles must lie within mod s =1

d) all the roots of the characterstic equation must be located on the left side of the jw axis.

19.Two systems with impulse responses h1(t) and h2(t) are connected in cascade. Then the overall impulse response of the cascaded system is given by

a) product of h1(t) and h2(t)

b) sum of h1(t) and h2(t)

c) convolution of h1(t) and h2(t)

d) subration of  h2(t) and h1(t)

20. A source Vs(t) = V cos 100πt has an internal  impedence of  (4+j3) Ohm. If a purely resistive load connected to this source has to extract the maximum power out of the source, its value in Ohm should be

a) 3

b) 4

c) 5

d) 7 

GATE 2012 MECHANICAL PAPER SOLVED

1. In abrasive jet machining, as the distance between the nozzle tip and the work surface increases, the material removal rate
a) increases continuously
b) decreases continuously
c) decreases, becomes stable and then increases
d) increases, becomes stable and then increases
ans. d

4. During normalizing process of steel, the specimen is heated
a) between the upper and lower critical temperature and cooled in still air
b) above the upper critical temperature and cooled in furnace
c) above the upper critical temperature and cooled in still air
d) between the upper and lower critical temperature and cooled in furnace
ans. c

7.Stream enters an adiabatic turbine operating at steady state with an enthalpy of 3251.0 kj/kg and leaves as the mixture at 15 kPa with quality (dryness fraction) 0.9. The enthalpies of the saturated liquid and vapor at 15 kPa are hf=225.94kj/kg and hg=2598.3 kj/kg respectively. The mass flow rate of steam is 10 kg/s. Kinetic and potential enregy changes are negligible. The power output of the turbine in MW is
a) 6.5
b) 8.9
c) 9.1
d) 27.0
ans. b

8. The following are the data for two crossed helical gears used for speed reduction:
Gear 1: pitch circle diameter in the plane of rotation 80 mm and helix angle 30'
Gear 2: pitch cirlce diameter in the plane of rotation 120 mm and helix angle 22.5'
If the input speed is 1440 rpm , the output speed in rpm is
a) 1200
b) 900
c) 875
d) 720
ans. b

10. A thin walled spherical shell is subjected to an internal pressure. If the radius of the shell is increased by 1% , with the internal pressure remaining the same, the percentage change in the circumferential (hoop) stress is
a) 0
b) 1
c) 1.08
d) 2.02
ans. d

11. The area enclosed between the straight line y=x and the parabola y= x.x in the x-y plane is
a) continuous and differentiable
b) non-continuous and differentiable
c) continuous and non-differentiable
d) nither continuous nor differentiable
ans. c

13. Which one of the following is NOT a decision taken during the aggregate production planning stage?
a) Scheduling  of machines
b) Amount of labour to be committed
c) Rate at which production should happen
d) Inventory to be carried forward
ans. a

15.A CNC vertical milling machine has to cut a straight slot of 10 mm width and 2mm depth by a cutter of 10 mm diameter between points (0,0) and (100,100) on the XY plane (diemensions in mm). The feed rate used for milling is 50 mm/min. Milling time for the slot (in seconds) is
a) 120
b) 170
c) 180
d) 240
ans. a

16. A solid cylinder diameter 100 mm and height 10 mm is forged between two frictionless flat dies to a height of 25 mm. The percentage change in diameter is
a) 0
b) 2.07
c) 20.7
d) 41.4
ans. d

18. Which one of the following configuration has the highest fin effectiveness?
a) Thin, closely spaced fins
b) Thin , widely spaced fins
c) Thick, widely spaced fins
d) Thick, closely spaced fins
ans. a

21. A circular solid disc of unifrom thickness 20 mm , radius 200 mm and mass 20 kg , is used as flywheel. If it rotates at 600 rpm, the kinetic energy of the flywheel, in joules is
a) 395
b) 790
c) 1580
d) 3160
ans. b

23. For a long slender column of uniform cross section, the ratio of critical buckling load for the case with both ends clamped to the case with both ends hinged is
a) 1
b) 2
c) 4
d) 8
ans. c

28.In a single pass drilling operation, a through hole 15 mm diameter is to be drilled in a steel plate of 50 mm thickness. Drill spindle speed is 500 rpm , feed is 0.2 mm/rev and drill point angle is 118' .Assuming 2 mm clearance at approach and exit, the total drill time (in seconds) is
a) 35.1
b) 32.4
c) 31.2
d) 30.1
ans. a

30. An incompressible fluid flows over a flat plate with zero pressure gradient. The boundary layer thickness 1 mm at a location where the Reynolds number is 1000 .If the velocity of the fluid alone is increased by a factor of 4, then the boundary layer thickness at the same location, in mm will be
a) 4
b) 2
c) 0.5
d) 0.25
ans. c

38. In a single pass rolling process using 410 mm diameter steel rollers, a strip of width 140 mm and thickness 8 mm undergoes 10% reduction of thickness. The angle of bite in radians is
a) 0.006
b) 0.031
c) 0.062
d) 0.600
ans. c

39. In a DC arc welding operation, the voltage-arc length characterstic was obtained as Varc=20+5l where the arc length l was varied between 5 mm and 7 mm . Here Varc denotes the arc voltage in Volts. The arc current was varied from 400 A to 500 A . Assuming linear power source characterstic, the open circuit voltage and the short circuit current for welding operation are 
a) 45 V, 450 A
b) 75 V, 750 A
c) 95 V, 950 A
d) 150 V, 1500 A
ans. c

41.Water (Cp=4.18 kj/kg.K) at 80'C enters a counterflow heat exchanger with a mass flow rate of 0.5 kg/s. air(Cp= 1kj/kg.K) enters at 30'C with a mass flow rate of 2.09 kg/s . If the effectiveness of the heat exchanger is 0.8, the LMTD (in 'C) is
a) 40 
b) 20 
c) 10
d) 5
ans. c

43. A solid circular shaft needs to be designed to transmit a torque of 50 N.m. If the allowable shear stress of the material is 140 MPa, assuming a factor of safety of 2, the minimum allowable design diamter in mm is 
a) 8
b) 16
c) 24
d) 32
ans. b

45. A box contains 4 red balls and 6 black balls. Three balls are selected randomly from the box one after another, without replacement. The probability that the selected set contains one red ball and two black balls is
a) 1/20 
b) 1/12
c) 3/10
d) 1/2
ans. d

47. x+2y+z=4
     2x+y+2z=5
    x-y+z=1
The system of algebraic equations given above has
a) a unique solution of x=1,y=1 and z=1
b) only the two solutions of (x=1,y=1,z=1) and (x=2,y=1,z=0).
c) infinite number of solutions
d) no feasible solution
ans. c

56. choose the most appropriate alternative from the options given below to complete the following sentence:
Suresh's dog is the one_____ was hurt in the stampede.
a) that
b) which
c) who
d) whom
ans. a

57. fill in the blank
Despite several ________ the mission succeeded in its attempt to resolve the conflict.
a) attempts
b) setbacks
c) meetings
d) delegations
ans. b

59. which one of the following options is the closest in the meaning of the word given below?
Mitigate
a) Diminish
b) Divulge
c) Dedicate
d) Denote
ans. a

61. Given the sequence of terms AD CG FK JP , the next term is
a) OV
b)OW
c) PV
d) PW
ans. a

GATE PAPER ELECTRICAL 2012 SOLVED

TECHNICAL QUESTIONS 

2. The typical ratio of latching current to holding current in a 20 A thyristor is
a) 5.0
b) 2.0
c) 1.0
d) 0.5
ans. 2

4. The sequence components of the fault current are as follows I+ =j1.5 pu, I- = -j0.5 pu, Izero= -j 1 pu. The type of fault in the system is
a) LG
b) LL
c) LLG
d) LLLG
ans. c

14. The slip of an induction motor normally does not depend on
a) rotor speed
b) synchronous speed
c) shaft torque
d) core-loss component
ans. d

19. The bridge method commonly used for finding the mutual inductance is
a) Heaviside Campbell bridge
b) Schering bridge
c) De Sauty bridge
d) Wien bridge
ans. a

27. The locked rotor current in a 3-phase , star connected 15kw , 4-pole , 230V , 50Hz induction motor at rated conditions is 50 A. Neglecting losses and magnetizing current, the approximate locked rotor line current drawn when the motor is connected to a 236 V , 57 Hz supply is
a) 58.5 A
b) 45.0 A
c) 42.7 A
d) 55.6 A
ans. b

28. An analog voltmeter uses external multiplier settings. With a multiplier setting of 20 Kohm , it reads 440V and with a multiplier setting of 80 Kohm, it reads 352 V . For a multiplier setting of 40 Kohm , the voltmeter reads
a) 371 V
b) 383 V
c) 394 V
d) 406 V
ans. d

36. A fair coin is tossed till a head appears for the first time. The probability that the number of required tosses is odd, is
a) 1/3
b) 1/2
c) 2/3
d) 3/4
ans. c

39. A cylindrical rotor generator delivers 0.5 pu power in the steady-state to an infinite bus through a transmission line of reactance 0.5 pu. The generator no-load voltage is 1.5 pu and the infinite bus voltage is 1 pu. The inertia constant of the generator is 5 MW-s/MVA and the generator reactance is 1 pu.The critical clearing angle, in degrees, for a three-phase dead short circuit fault at the generator terminal is
a) 53.3
b) 60.2
c) 70.8
d) 79.6
ans. d

GENERAL APTITUDE

56. Choose the most appropriate word from the options given below to complete the following sentence:
Given the seriousness of the situation that he had to face , his_____ was impressive.
a) beggary
b) nomenclature
c) jealously
d) nonchalance
ans. d

58. Which one of the following options is the closet in meaning to word given below?
 Latitude
a) Eligibilty
b) Freedom
c) coersion
d) Meticulouness
ans. b

59. fiill in the blank with appropriate alternative from the options
If the tired soldier wanted to lie down, he_____ the matress out on the balcony.
a) should take
b) shall take
c) should have taken
d) will have taken
ans. a

60. find out error in sentence
I requested that he should be given the driving test today instead of tomorrow.
a) requested that
b) should be given
c) the driving test
d) instead of tomorrow
ans. b

61. There are eight bags of rice looking alike , seven of which have equal weight and one is slightly heavier. The weighing balance is of unlimited capacity. Using this balance , the minimum number of weighings required to identify the heavier bag is
a) 2
b) 3
c) 4
d) 8
ans. a

62. One of the legacies of the Roman legions was discipline. In the legions, military law prevailed and discipline was brutal. Discipline on the battlefield kept units obedient , intact and fighting, even when the odds and conditions were against them.
which one of the following statements best sums up the meaning of the above passage?
a) Through regimentation was the main reason for the efficiency of the Roman legions even in adverse circumstances.
b) The legions were treated inhumanly as if the men were animals.
c) Discipline was the armies' inheritance from their seniors.
d) The harsh discipline to which the legions were subjected to led to the odds and conditions being against them.
ans. a

64. Raju has 14 currency notes in his pocket consisting of only Rs 20 notes and Rs. 10 notes. The total money value of the notes is Rs 230 . The number of Rs. 10 notes that Raju has is
a) 5
b) 6
c) 9
d) 10
ans. a

65. A and B are friends. They decide to meet between 1 pm and 2 pm on a given day. There is a condition that whoever arrives first will not wait for the other for more than 15 minutes . The probability that they will meet on that day is
a) 1/4
b) 1/6
c) 7/16
d) 9/16
ans. c