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GATECounsellor EE Sample Paper 2011

GATECounsellor | E-mail id: [email protected] Page 1 of 19

EE: Electrical Engineering

Duration: Two and Half Hours Maximum Marks: 85

Read the Instructions carefully.

1. All Questions in this Paper are Objective type.2. There are a total of 55 questions carrying 85 marks.3. Questions Q.1 – Q. 25 will carry 1-mark each, questions Q.26 – Q.55 carry 2-marks

each.

4. Questions Q.50 – Q.51 are common data questions and question pairs (Q.52 – Q.53), and (Q.54 – Q.55) are linked answer questions. The answer to the second

questions of the linked answer question depends on the answer to the first

question of the pair. If the first question is wrongly answered or is un-attempted,

then the answer to the second question will not be evaluated.

5. Un-attempted questions will carry zero marks.6. Wrong answers will carry NEGATIVE marks. For Q.1 – Q.25, 1/3 mark will be

deducted for each wrong answer. For Q.26–

Q.51, 2/3 mark will be deducted for

each wrong answer.

7. The questions pairs (Q.52 – Q.53), and (Q.54 – Q.55) are questions with linkedanswers. There will be negative marks only for wrong answers to the first

question of the linked answer question pair i.e. for Q.52 and Q.54, 2/3 will be

deducted for wrong answer. There is no negative marking for Q.53 and Q.55.


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Questions 1-25 carry 1 Mark each.

1. If the determinant of 2×2 matrix is 96 and trace of the matrix is 22, then what are theEigen values?

(a) 16, 6(b) 24, 4(c) 11, 11(d) 12, 8

2. If has a eigen values -1, -1, 0, 1 and 1, then(a) 0(b) 32(c) 162(d) None of these

3. The induced emf in a dc machine while running at 750 rpm is 220V. What is thepercentage increase in field flux for the induced emf of 250V and speed of 700 rpm?

(a) 10%(b) 25%(c) 25%(d) 22%

4. The 250V shunt motor on no load runs at 1000rpm and draws 5A from the line. Thearmature resistance is and the field resistance is . Calculate the speed of

the motor when it is loaded and draws a current of 50 A. The armature reaction

weakens the field by 3%.

(a) 800rpm(b) 850rpm(c) 994 rpm(d) 1000rpm

5. The polarity of commutating pole in dc generator and dc motor is/are:(a) Same as that of main pole immediately ahead of in both dc generator and motor.(b) Same as that of main pole immediately behind of in both dc generator and motor.(c) Is of main pole immediately ahead in generator and immediately behind in motor.(d) Is of main pole immediately behind in generator and immediately ahead in motor.


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10. Out of the given options find the correct one(i) (ii)

I

I

ON ON

OFF OFF

V V

I

ON

OFF V

(iii)

The correct match is

(a) MOSFET -(i) , BJT-(ii) , DIODE-(iii)(b) DIODE -(ii) , IGBT-(ii) , MOSFET-(iii)(c) DIODE -(i) , BJT-(iii) , MOSFET-(ii)(d) None of the above

11. In the circuit shown in figure, the value of Vx is(a) 17.5 V(b) -17.5 V(c) 35 V(d) -35 V

2Ω

2Ω

4Ω + -

Vx

10 A


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1Ω

1Ω 1Ω 1Ω

1Ω 1Ω

6 V

12. The power delivered by the source in thefollowing circuit is,

(a) 3 W(b) 6 W(c) 9 W(d) 12 W

13. For the given buck convertor, find the condition of discontinuous conduction mode(boundary condition)

(a) (b) (c) (d)

14. Consider the below subroutineLXI SP,2400H

MVI C,01H

PUSH B

POP PSW

RET

After execution of this subroutine contents in the zero flag and carry flag will be

respectively….


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t

t

I

tr

V

Solid Line: Ideal

Dot Line: Actual

C

E

G

(a) set, reset(b) set, set(c) reset, set(d) Not affected

15. Find the direction derivative of at in thedirection of

(a) + 1.789 (b) – 1.789 (c) + 17.89 (d) – 17.89

16. For the given IGBT (Insulated gate bipolar transistor) having the transientcharacteristic as shown when connected in Type-A chopper, find the turn on

energy loss.

(a) (b) (c)

(d)

17. In the following circuit, R is varied but the other elements remaining the same:when R = ∞, V0 = 6 V

when R = 0, I = 3 Awhen R = 4Ω, the value of V0 is,

(a) 4 V(b) 2 V(c) 1 V(d) 3 V

I

R

-

+

V

V

Resistors


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18. Find the type of the signal x(t) as shown,

(a) Power signal with P=A2 (b) Energy Signal with E=A2/2(c) Power Signal with P=A2/2(d) Neither Energy nor Power Signal.

19. In the given circuit the current waveform through inductor in continuousconduction mode is

(fig: Buck convertor )

d=D =duty ratio

= Switching time

Note: Y-axis denote the inductor current iL.

(a)

Exponential Decay (Ae-t),

A is finite

t

x(t)


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(b)

(c)

(d)

20. Match the following,I II

1. A. Periodic2. B. Aperiodic3.

4.


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

21. If in the logic equation,

Then,

(a) (b) (c) (d)

22. The p.u. impedance of a transmissionline is Zo on kVAo , kVo base rating. If thebase rating is changed to kVAn , kVn then the p.u.impedanceof that transmission

line will be given by :

(a) Zn = Zo(kVn/kVo)2(kVAn/kVAo)(b) Zn = Zo(kVn/kVo)2(kVAo/kVAn)(c) Zo = Zn(kVo/kVn)2(kVAn/kVAo)(d) Zo = Zn(kVn/kVo)2(kVAo/kVAn)

23. In the presence of earth the capacitance of a transmission line:(a) Decreases(b) Increases(c) Remains same (no effect of earth)(d) Can be either of the above

24. The correct relationship between sending and receiving end voltage andcurrentis:

(a) Vs = Vr cosh( γl) – Ir Zc sin( γl)Is = Ir cosh( γl) – (Vr /Zc )sinh( γl)

(b) Vr = Vs cosh( γl) – Is Zc sin( γl)Ir = Is cosh( γl) – (Vs/Zc )sinh( γl)

(c) Vs = Vr cosh( γl) – Ir Zc sin( γl)Is = Ir cosh( γl) – (Vr/Zc )sinh( γl)

(d) Vr = Vs cosh( γl) – Is Zc sin( γl)Ir = Is cosh( γl) – (Vs /Zc )sinh( γl)


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Where, Vs and Is are sending end voltage and current and Vr and Ir are receiving end

voltage and currents, γ is the propagation constant .

25. For a balanced 3-φ Y-connected load, the relation between the line-line voltage(Vab) and line-neutral voltage (Van) is given by:

(a) oan abV 3V 30 (b) oan abV (V / 3) 30 (c) oab anV 3V 30 (d) oab anV 3V 30

Questions 26-55 carry 2 Marks each.

26. Consider the following circuit

The ammeter A1 reads 5 A and A2 reads 3 A. The reading of ammeter A is

(a) 8 A(b) 0 A(c)

2 A

(d) 5.83 A27. Find the system gain, type and order for

(a) 70,3,7(b) 70,2,3(c) 16.27,2,7(d) 16.27,3,7

A

A1 A2


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-1/b

1/b

A

DB

C

28. Find the gain of the system given below,

(a) (b) (c) (d)

29. Match the following,H(s):

1. 2. 3. 4.

(a) 1-A, 2-B, 3-C, 4-D(b) 1-B, 2-D, 3-A, 4-C(c)

1-D, 2-C, 3-A, 4-B

(d) 1-A, 2-D, 3-B, 4-C

_

+

+

+

+

+G

H

H

G

R(s

C(s


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30. For power system configuration given in figure the Ybus matrix will be:

(a) [ ]BUSY 20 36.87= Ð - (b)

BUS

20 53.13 20 126.87

20 126.87 20 53.13Y

(c) BUS20 53.13 20 126.87

Y20 126.87 20 53.13

(d) BUS

20 36.87 20 143.13

20 143.13 20 36.87Y

31. The flux linkage between points P1 and P2 external to the conductor C (as shownin figure) will be given by :

(a) 7 21

2 10 ln( ) D r

D r

(b) 7 21

2 10 ln( ) D

D

(c) 7 21

cos2 10 ln( )

cos

D r

D r

(d) 7 21

sin2 10 ln( )

sin

D r

D r

32. An LTI system is invertible if, hinv[n] is impulse response of inverse system ofh[n].Where, hinv[n] is impulse response of inverse system of h[n].

(a) (b) (c) (d)


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33. Out of the following interrupt of 8085 microprocessor which is not a vectoredone?

(a) RST 5.5(b)

TRAP(c) RST 6.5

(d) INTR34. A SCIM has slip 5% at full load and starting current is 4 times its full load value.

The starting torque in pu would be,

(Note: Assume starter impedance and magnetizing current negligible)

(a) 1pu(b) 0.8pu(c) 3.5pu(d) 5pu

35. In vector hardware interrupt, if on a fire alarm signal RST 7.5 interrupts isactivated, then which address would program counter store, if RST 5.5

corresponds to 002CH,

(a) 0032H(b) 001CH(c) 003CH(d) 0010H

36. 1,2 and 3 voltmeters are connected in series(400V each) with sensitivity100KΩ/V, 150KΩ/V and 200KΩ/V respectively. The reading of 1 ,2 and 3 will be, (A) 133.3, 200, 266.7(B) 266.7, 200, 133.3(C) 200,200,200(D) 100,200,300

37. In a 20 km electrical distribution line with a combination of linear and non linearload the receiving end, the current drawn has electrical noise. On analyzing the

current and the voltage at the receiving end of distributor following current andvoltage components were found:

Voltage,

V= 200sin(314t)+50 sin (3*314t) + 10 sin(6*314t)

Current,

I = 15sin(314t-36°) +10sin(2*314t-45°)+ 6.3sin(3*314t) + 1.38sin(13*314t-20°)

Find the total active power consumed. Assume the line to be have no capacitance

to earth, the resistance per phase of line is : Rs= 0.3 ohm/ km.The reactance of line

(at 314 rad/sec.)= 0.5 ohm/km


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V(0,0)

A

C

R=0

Locus of IXc

R

VI

Note: The missing data may be assumed to be one per unit on its own base.

(a)1371 watt

(b)1307.1 watt

(c) 1093.45 watt(d)Cannot be calculated

38. Find the Z parameters of the following circuit:4Ω

1 8Ω 8Ω 2

4Ω

(a) Z11= 6 ohm, Z12= 2 ohm, Z21= 2ohm, Z22= 6 ohm(b) Z11= 12 ohm, Z12= 4 ohm,Z21= 2ohm, Z22= 12 ohm(c) Z11= 16 ohm, Z12= 4 ohm, Z21= 4ohm, Z22= 16 ohm(d) Z11= 12 ohm, Z12= 4 ohm, Z21= 2ohm, Z22= 16 ohm

39. In the given circuit find the locus of current I (rms value)with respect to thevariation in the parameter Xc, and the centre of locus, if the applied voltage is V

volts (rms).

(a) A( , C(b) A( ,C(c) A( , C(d) A( ,C


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40. A 200 volt, 875 rpm, 150A separately excited DC motor has an armatureresistance of 0.06 Ω . It is fed from a single phase fully controlled rectifier with an

ac source voltage of 220 volts, 50 Hz . Assuming the rectifier operates in

Continuous Conduction Mode. Calculate the firing angle for rated motor torque

and -500 rpm.

(a) 135 °(b) 120°(c) 60°(d) 150°

41. Match the correct option for the braking of motor.(i) Plugging (A) The variable resistance is introduced in seriesto bring the motor to halt at smooth rate.

(ii) Regenerative Braking (B) The supply voltage assist the back emf to bring

the motor quickly to zero.

(iii) Dynamic Braking (C) The back emf is more than the applied voltage

(a) i-A, ii-C, iii-B(b) i-B, ii-C, iii-A(c) i-B, ii-A, iii-C(d) i-C, ii-B, iii-A

42. A solid nonmagnetic conductor of circular cross section has its axis along zdirection and carries uniformly distributed current of 60 A in a z direction. If

conductor has the radius of 4 mm the magnetic flux density at ρ = 3 mm is:

(a) 1.65 mT(b) 2.25 mT(c) 3.33 mT(d) 1.75 mT

43. A 25 kW , 380 volts, 3-phase wound rotor type Induction Motor with negligiblestator impedance runs at 5% slip at rated torque and the slip at maximum torqueis 4 times the full load value If the rotor resistance is increased to 4 times then

what will be speed corresponding to maximum torque.

(a) 0.8 Ns (b) 0.6 Ns (c) 0.2 Ns (d) 0.95 Ns


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44. In a 3-phase, 4-pole, 50 Hz, 400 volts delta connected induction motor, themaximum torque is 50 Nm at 15 % slip. If rotor resistance is 0.3 Ω find the

external resistance to be inserted to make starting torque 75% of full load value

with voltage reduced to 360 volts.

The stator resistance can safely be assumed to be negligible.

(a) 0.573 Ω (b) 0.746 Ω (c) 1.044 Ω (d) 1.333 Ω

45. How many time will the instruction NXT be executed the program.MVI A,01H

MVI D,12H

NXT: NOP

ADD DRAL

JNC NXT

NOP

HLT

(a) 3(b) 4(c) 2(d) 5

46. The value of V0/Vin is,

(a) -3(b) -4(c) -2(d) -3/2

iV

k 1

k 1

k 1

k 1

oV


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Ts

DTs

R Vo C

(2)

DTs (1)

D’Ts

Vg

L+

-

47. The hysteresis and eddy current losses in a single phase transformer of 200volts, 50 Hz are Px and Py. If the voltage is changed to 100 volts, 25 Hz then

percentage change in these values are respectively:

(a) 50, 50.(b) 25, 75.(c) 75, 25.(d) 37.5, 50.

48. A 3-phase stator and rotor winding of a wound rotor induction motor aresupplied with some voltage of frequency ω. If the rotor speed is ωr and

synchronous speed is ω, then the resultant flux in space has which of the

following characteristics:

(a) Rotates at speed Ns(b)

Rotates at -(Ns+Nr)

(c) Rotates at -Ns+Nr(d) Rotates at (Ns+Nr)

49. For given convertor circuit if duty rate is D. Finds

(a) (b) (c) (d)


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Common Data Questions:

Common Data Questions 50 and 51:

50. A transmission line has the configuration as shown in figure. If the inductance ofconductor X and Y are Lx and Ly respectively the line inductance will be given by:

(a) Lx + Ly(b) LxLy /(Lx+Ly)(c) (1/Lx)+ (1/Ly)(d) LxLy

51. The GMR to calculate inductance of side X of theabove conductor will be :

(a) 0.523 m(b) 0.481 m(c) 0.1374 m(d) 1.213 m

Linked Question:

Linked Questions for Q.52-Q.53

52. A 50Hz A.C. synchronous generator having H=5MJ/MVA is delivering power of0.8 p.u. to an infinite bus through a purely reactive network when the occurrence

of a fault reduces the output to zero. The maximum power that could be

delivered is 1.6 p.u. . When the fault is cleared, the original network condition

exists. The critical clearing angle for the power system will be:

(a) 79.56o (b) 36.33o (c) 82.12o (d) 68.87o

53. For the above question the critical clearing time will be:(a) 0.1855 sec(b) 0.0663 sec(c) 0.2 sec(d) 0.1641 sec


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Linked Questions for Q.54-Q.55

54. For this circuit, value of VCEQ& ICQ are,(a) 3.52V, 0.8mA(b) 6.75V,1.05mA(c) 3.52V, 1.05mA(d) 6.75V,0.8mA

55. For previous question, the input resistance and ac voltage gain V0/Vin is(a) 3.33KΩ, -101.5(b) 0.73KΩ, -203(c) 0.73KΩ, -101.5(d) 3.33KΩ, -203

END OF QUESTION PAPER

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