GATE 2003 Electrical Engineering Question Papers – GATE Electrical Sample papers

GATE 2003 Electrical Engineering Question Papers or GATE Electrical Sample papers is as follows. Check here for Gate Electrical Question papers so that it will be helpful to write your Gate examination.

GATE 2003 Electrical Engineering Question Papers
Q.1 – Q.30 CARRY ONE MARK EACH

1. Fig.Q1 shows the waveform of the current passing through an inductor of
resistance 1 and inductance 2 H. The energy absorbed by the inductor in the
first four seconds is
(a) 144 J
(b) 98 J
(c) 132 J
(d) 168 J

2. A segment of a circuit is shown in Fig.Q2. V = 5V, V = 4 sin 2t. The voltage V L is given by
(a) 3 œ 8 cos 2t
(b) 32 sin 2t
(c) 16 sin 2t
(d) 16 cos 2t

3. In the Fig.Q3. Z =10 -60°, A2=10 60°, Z =50 53.13°. The Venn impedance
seen from X-Y is
(a) 56.6 45°
X
(c) 70 30°
(d) 34.4 65°

4. Two conductors are carrying forward and return current of +I and œI as shown in Fig.Q4. The magnetic field intensity H at point P is

5. Two infinite strips of width w m in x direction as shown in Fig.Q5, are carrying forward and return currents of +I and œI in the z direction. The strips are separated by a distance of xm. The inductance per unit length of the configuration is measured to be L H/m. If the distance of separation between the strips is now reduced to , the inductance per unit length of the configuration

(b) L/4 H/m
(c) L/2 H/m
(d) 4L H/m

6. A single phase transformer has a maximum efficiency of 90% at full load and unity power factor. Efficiency at half load at the same power factor is
(a) 86.7% (b) 88.26% (c) 88.9% (d) 87.8%

7. Group I lists different applications and Group II lists the motors for these
applications. Match the application with the most suitable motor and choose the right combination among the choices given thereafter

Group I Group II
P Food mixer 1 Permanent magnet dc motor
Q Cassette tape recorder 2 Single phase induction motor
R Domestic water pump 3 Universal motor
S Escalator 4 Three phase induction motor
5 DC series motor
6 Stepper motor

(a) P œ 3 Q œ 6 R œ 4 S – 5 (b) P œ 1 Q œ 3 R œ 2 S – 4
(c) P œ 3 Q œ 1 R œ 2 S – 4 (d) P œ 3 Q œ 2 R œ 1 S – 4

8. A stand-alone engine driven Synchronous generator is feeding a partly inductive load. A capacitor is now connected across the load to completely nullify the inductive current. For this operating condition.
(a) the field current and fuel input have to be reduced
(b) the field current and fuel input have to be increased
(c) the field current has to be increased and fuel input left unaltered
(d) the field current has to be reduced and fuel input left unaltered

9. Curves X and Y in Fig.Q9 denote open circuit and full-load zero power factor (zpf) characteristics of asynchronous generator. Q is a point on the zpf characteristics at 1.0 p.u. voltage. The vertical distance PQ in Fig.Q.9 gives the voltage drop across

(a) Synchronous reactance (b) Magnetizing reactance
(c) Potier reactance
(d) Leakage reactance

10. No-load test on a 3-phase induction motor was conducted at different supply voltages and a plot of input power versus voltage was drawn. This curve was extrapolated to intersect the y-axis. This intersection point yields
(a) Core loss (b) Stator copper loss
(c) Stray load loss (d) Friction and windage loss

11. Bundled conductors are mainly used in high voltage overhead transmission lines to
(a) reduce transmission line losses
(b) increase mechanical strength of the line
(c) reduce corona (d) reduce sag

12. A power system consists of 300 buses out of which 20 buses are generator buses, 25 buses are the ones with reactive power support and 15 buses are the ones with fixed shunt capacitors. All the other buses are load buses. It is proposed to perform a load flow analysis for the system using Newton-Raphson method. The size of the Newton-Raphson Jacobian matrix is
(a) 553 × 553 (b) 540 × 540 (c) 555 × 555 (d) 554 × 554

13. Choose two appropriate auxiliary components of a HVDC transmission system from the following
P D.C. line inductor
Q A.C. line inductor
R Reactive power sources
S Distance relays on D.C. line
T Series capacitance of A.C. line
(a) P and Q (b) P and R (c) Q and S (d) S and T

14. A round rotor generator with internal voltage E = 2.0 p.u. and X = 1.1 p.u. is connected to a round rotor synchronous motor with internal voltage E = 1.3 p.u.
and X = 1.2 p.u. The reactance of the line connecting the generator to the motor is 0.5 p.u. when the generator supplies 0.5 p.u. power, the rotor angle difference between the machines will be
(a) 57.42° (b) 1° (c) 32.58° (d) 122.58°

15. The interrupting time of a circuit breaker is the period between the instant of
(a) initiation of short circuit and the arc extinction on an opening operation
(b) energizing of the trip circuit and the arc extinction on an opening operation
(c) initiation of short circuit and the parting of primary arc contacts
(d) energizing of the trip circuit and the parting of primary arc contacts

16. The variation of drain current with gate-to-source voltage
I V – characteristic of a MOSFET is shown in Fig.Q.16. The MOSFET is
(a) an n-channel depletion mode device
(b) an n-channel enhancement mode device
(c) a p-channel depletion mode device
(d) a p-channel enhancement mode device

17. In the circuit of Fig.Q17, assume that the transistor has
h V V 99 and 0.7 . The value of collector current I of the transistor is = =
approximately
(a) [3.3/3.3] mA
(b) [3.3/(3.3+.33] mA
(c) [3.3/33] mA
(d) [3.3/(33+3.3] mA

18. For the circuit of Fig.Q18 with an ideal operational amplifier, the maximum phase shift of the output V with reference to the input V is
(a) 0° (b) -90° (c) +90° (d) 180°

19. Fig.Q19 shows a 4 to 1 MUX to be used to implement the sum S of a 1-bit full adder with input bits P and Q and the carry input C . Which of the following in combinations of inputs to I , I , I and I of the MUX will realize the sum S?

20. When a program is being executed in an 8085 microprocessor, its Program Counter contains
(a) the number of instructions in the current program that have already been executed
(b) the total number of instructions in the program being executed
(c) the memory address of the instruction that is being currently executed
(d) the memory address of the instruction that is to be executed next

21. A control system is defined by the following mathematical relationship

The response of the system as t ‰ 8 is
(a) x = 6 (b) x = 2 (c) x = 2.4 (d) x = -2

22. A lead compensator used for a closed loop controller has the following transfer  For such a lead compensator
(a) a < b (b) b < a (c) a > Kb (d) a < Kb

23. A second order system starts with an initial condition of 2 without any external input. The state transition matrix for the system is given by The …
state of the system at the end of 1 second is given by
(a) 0.271 (b) 0.135 (c) 0.271 (d) 0.135

24. A Manganin swamp resistance is connected in series with a moving coil ammeter consisting of a milli-ammeter and a suitable shunt in order to
(a) minimize the effect of temperature variation
(b) obtain large deflecting torque
(c) reduce the size of the meter
(d) minimize the effect of stray magnetic fields

25. The effect of stray magnetic fields on the actuating torque of a portable
instrument is maximum when the operating field of the instrument and the stray fields are
(a) perpendicular (b) parallel
(c) inclined at 60° (d) inclined at 30°

26. A reading of 120 is obtained when a standard inductor was connected in the circuit of a Q-meter and the variable capacitor is adjusted to a value of 300 pF. A lossless capacitor of unknown value C is then connected in parallel with the variable capacitor and the same reading was obtained when the variable capacitor is readjusted to a value of 200 pF. The value of C in pF is
(a) 100 (b) 200 (c) 300 (d) 500

27. Fig.Q27 shows a thyristor with the standard terminations of anode (A), cathode
(K), gate (G) and the different junctions named J1, J2 and J3. When the thyristor is turned on and conducting

(a) J1 and J2 are forward biased and J3 is reverse biased
(b) J1 and J3 are forward biased and J2 is reverse biased
(c) J1 is forward biased and J2 and J3 are reverse biased
(d) J1, J2 and J3 are all forward biased

28. Fig.Q28 shown a MOSFET with an integral body diode. It is employed as a power switching device in the ON and OFF states through appropriate control. The ON and OFF states of the switch are given on the V -I plane by
(a) Fig.A (b) Fig.B (c) Fig.C (d) Fig.D

29. The speed/torque regimes in a dc motor and the control methods suitable for the same are given respectively in Group II and Group I

Group I Group II
P Field Control 1 Below base speed
Q Armature Control 2 Above base speed
3 Above base torque
4 Below base torque

(a) P œ 1; Q – 3 (b) P œ 2; Q – 1 (c) P œ 2; Q – 3 (d) P œ 1; Q – 4

30. A fully controlled natural commuted 3-phase bridge rectifier is operating with a  a firing angle =30°. The peak to peak voltage ripple expressed as a ratio of the peak output dc voltage at the output of the converter bridge is

Q.31 – Q.90 CARRY TW O MARKS EACH

31. In the circuit of Fig.Q31, the magnitudes of V and V are twice that of V . The inductance of the coil is C C  (a) 2.14 mH

(b) 5.30 H
L V
L
(c) 3.18 mH
(d) 1.32 H

32. In Fig.Q32, the potential difference between points P and Q is
(a) 12 V
(b) 10 V
(c) -6 V
(d) 8 V

33. Two ac sources feed a common variable resistive load as shown in Fig.Q33. Under the maximum power transfer condition, the power absorbed by the load resistance R is
(a) 2200 W
(b) 1250 W
(c) 1000 W
(d) 625 W

34. In Fig.34, the value of R is
(a) 10
(b) 18
(c) 24
(d) 12

35. A balanced delta connected load of (8+j6) per phase is connected to a 400 V, 50 Hz, 3-phase supply lines. If the input power factor is to be improved to 0.9 by connecting a bank of star connected capacitors the required kVAR of the bank is
(a) 42.7 (b) 10.2 (c) 28.8 (d) 38.4

36. In the circuit shown in Fig.Q36, the switch S is closed at time t = 0. the voltage across the inductance at t = 0 , is +
(a) 2V (b) 4V (c) -6V (d) 8V

37. The h-parameters for a two-port network are defined by
» ÿ » ÿ » ÿ E h h I
= . For the two-port network shown in Fig.Q37, the value of h is given by
(a) 0.125
(b) 0.167
(c) 0.625
(d) 0.25

38. A point charge of +1 nC is placed in a space with a permitivity of 8.85 × 10 F/m
as shown in Fig.Q38. The potential difference V between two points P and Q at P Q
distances of 40 mm and 20 mm respectively from the point charge is
(a) 0.22 kV
(b) -225 V
(c) -2.24 kV
(d) 15 V

39. A parallel plate capacitor has an electrode area of 100 mm , with a spacing of 0.1mm between the electrodes. The dielectric between the plates is air with a permittivity of 8.85 × 10 F/m. The charge on the capacitor is 100 V. the stored energy in the capacitor is
(a) 8.85 pJ (b) 440 pJ (c) 22.1 nJ (d) 44.3 nJ

40. A composite parallel plate capacitor is made up of two different dielectric materials with different thickness (t and t ) as shown in Fig.Q40. The two different dielectric materials are separated by a conducting foil F. The voltage of the conducting foil is
(a) 52 V
(b) 60 V
(c) 67 V
(d) 33 V

41. Fig.Q41 shows an ideal single-phase transformer. The primary and secondary coils are wound on the core as shown. Turns ratio = 2. The correct phasors 1 ÷
of voltages E , E currents I , I and core flux F are as shown in
(a) Fig. A (b) Fig. B (c) Fig. C (d) Fig. D

42. To conduct load test on a dc shunt motor, it is coupled to a generator which is identical to the motor. The field of the generator is also connected to the same supply source as the motor. The armature of the generator is connected to a load resistance. The armature resistance id 0.02 p.u. armature reaction and mechanical losses can be neglected. With rated voltage across the motor, the load resistance across the generator is adjusted to obtain rated armature current in both motor and generator. The p.u. value of this load resistance is
(a) 1.0 (b) 0.98 (c) 0.96 (d) 0.94

43. Fig.Q43 shows a -Y connected 3-phase Í distribution transformer used to step down the voltage from 11000 V to 415 V line-to-line. It has two switches S and S . Under normal conditions S is closed and S is open. Under certain special conditions S is open and S is closed. In such a case the magnitude of the voltage across the LV b terminals a and c is
(a) 240 V
(b) 480 V
(c) 415 V
(d) 0 V

44. Fig.Q44 shows an ideal three-winding transformer. The three windings 1,2,3 of the transformer are wound on the same core as shown. The turn‘s ratio N :N :N is 4:2:1. A resistor of 10 is connected across winding-2. A capacitor of reactance 2.5 is connected across winding-3. Widing-1 is connected across a 400 V, ac supply. If the supply voltage phasor V = 400 0°, the supply current phasor I is given by
(a) (-10 + j10) A
(b) (-10 – j10) A
(c) (10 + j10) A
(d) (10 – j10) A

45. Following are some of the properties of rotating electrical machines
P Stator winding current is dc, rotor-winding current is ac
Q Stator winding current is ac, rotor-winding current is dc
R Stator winding current is ac, rotor-winding current is ac
S Stator has salient poles and rotor has commutator
T Rotor has salient poles and sliprings and stator is cylindrical
U Both stator and rotor have poly-phase windings

DC machines. Synchronous machines and Induction machines exhibit some of the above properties as given in the following table. Indicate the correct combination from this table

DC machines Synchronous machines Induction machines
(a) P.S Q.T R.U
(b) Q.U P.T R.S
(c) P.S R.U Q.T
(d) R.S Q.U P.T

46. When Stator and Rotor windings of a 2-pole rotating electrical machine are excited, each would produce a sinusoidal mmf distribution in the air gap with peak values F and F respectively. The rotor mmf lags stator mmf by a space s r angle d at any instant as shown in Fig.Q46. Thus, half of stator and rotor surfaces will form one pole with the other half forming the second pole. Further, the direction of torque acting on the rotor can be clockwise or counter-clockwise.

The following Table gives four sets of statements as regards poles and torque. Select the correct set corresponding to the mmf axes as shown in Fig.Q46.

Stator Rotor Rotor
Stator Surface CDA
Surface ABC Surface Surface cda Torque is forms
forms cda forms forms
(a) North Pole South Pole North Pole South Pole Clockwise
(b) South Pole North Pole North Pole South Pole Counter
clockwise
(c) North Pole South Pole South Pole North Pole Counter
clockwise
(d) South Pole North Pole South Pole North Pole Clockwise

47. A 4-pole, 3-phase, double layer winding is housed in a 36-slot stator for an ac machine with 60° phase spread. Coil span is 7 slot pitches. Number of slots in which top and bottom layers belong to different phases is
(a) 24 (b) 18 (c) 12 (d) 0

48. A 3-phase Inductor Motor is driving a constant torque load at rated voltage and frequency. If both voltage and frequency are halved, following statements relate to the new condition if stator resistance, leakage reactance and core loss are ignored.

P The difference between synchronous speed and actual speed remains same

Q The air-gap flux remains same
R The stator current remains same
S The p.u. slip remains same
Among the above, correct statements are
(a) All (b) P, Q and R (c) Q, R and S (d) P and S

49. A single phase induction motor with only the main winding excited would exhibit the following response at synchronous speed
(a) Rotor current is zero
(b) Rotor current is non-zero and is at slip frequency
(c) Forward and backward rotating fields are equal
(d) Forward rotating field is more than the backward rotating field

50. A dc series motor driving an electric train faces a constant power load. It is running at rated speed and rated voltage. If the speed has to be brought down to 0.25 p.u. the supply voltage has to be approximately brought down to
(a) 0.75 p.u. (b) 0.5 p.u. (c) 0.25 p.u. (d) 0.125 p.u.

51. The ABCD parameters of a 3-phase overhead transmission line are A = D =0.9 0
B = 200 90° and C = 0.95 × 10 90°S. At no-load condition a shunt inductive – reactor is connected at the receiving end of the line to limit the receiving end voltage to be equal to the sending end voltage. The ohmic value of the reactor is
(a) 8 (b) 2000 (c) 105.26 (d) 1052.6

52. A surge of 20 kV magnitude travels along a lossless cable towards its junction with two identical lossless overhead transmission lines. The inductance and the capacitance of the cable are 0.4 mH and 0.5 F per km. The inductance and