A) 25kW in (i) and 75kW in (ii) B) 25kW in (i) and 50kW in (ii)
C) 50kW in (i) and 75kW in (ii)D) 50kW in (i) and 50kW in (ii)
2. In the matrix equation Px = q, which of the following is a necessary condition for the existence of at least one solution for the unknown vector x:
A) Augmented matrix [Pq] must have the same rank as matrix P
C) Matrix P must be singular
B) Vector q must have only non-zero elements
D) Matrix P must be square
3. At an industrial sub-station with a 4 MW load, a capacitor of 2 MVAR is installed to maintain the load power factor at 0.97 lagging. If the capacitor goes out of serivce, the load power factor becomes
A) 0.85
B) 0.80 lag
C) 1.00
D) 0.90 lag
4. In the GH(s) plane, the Nyquist plot of the loop transfer function G(s)H(s) = [(pi)e-0.25]/s acesses through the negative real axis at the point
A) (-0.25, j0)
C) (-l, j0)
B) (-0.5, j0)
D) (-2, j0)5. For the scalar field u = x2/2 + y2/3, magnitude of the gradient at the point (1,3) is
A) sqrt (13/9)B) sqrt (9/2)C) sqrt (5)D) 9/2
6. A digital-to-analog converter with a full-scale output voltage of 3.5 V has a resolution close to 14m V. Its bit size is
A) 4B) 8
C) 16D) 32
7. A single-phase half-controlled rectifier is driving a separately excited dc motor. The dc motor has a back emf constant of 0.5 V/rpm. The armature urrent is 5 A without any ripple. The armature resistance is 2 ohms. The converter is working from a 280 V, single phase ac source with a firing angle of 80°. Under this operating condition, the speed of the motor will be
A) 339 rpmB) 359 rpm
C) 366 rpmD) 386 rpm
8. In relation to the synchronous machines, which one of the following tatements is false?
A) In salient pole machines, the direct-axis synchronous reactance is greater than the quadrature-axis synchronous reactance
B) The damper bars help the synchronous motor self startC) Short circuit ratio is the ratio of the field current required to produce the rated voltage on open circuit to the rated armature current
D) The V-curve of a synchronous motor represents the variation in the armature current with field excitation, at a given output power 19. The 8085 assembly language instruction that stores the content of H and L registers into the memory locations 2050H and 2051H , respectively, is
A) SPHL 2050H
B) SPHL2051H
C) SHLD 2050H
D) STAX 2050H
10. Two wattmeters, which are connected to measure the total power on a three phase system supplying a balanced load, read 10.5 kW and – 2.5 kW, respectively. The total power and the ower factor, respectively, are
A) 13.0 kW, 0.334
B) 13.0 kW, 0.684C) 8.0 kW, 0.52 D) 8.0 kW, 0.334 11. The insulation strength of an EHV transmission line is mainly governed by
A) load power factor
B) switching over-voltagesC) harmonicsD) corona 12. For the equation, s3-4s2+s+6=0, the number of roots in the left half of s-plane will be
A) zero
B) one
C) twoD) three 13. A dc potentiometer is designed to measure up to about 2 V with a slide wire of 800 mm. A standard cell of emf 1.18 V obtains balance at 600 mm. A test cell is seen to obtain balance at 680 mm. The emf of the test cell is
A) 1.00V
B) 1.34V
C) 1.50VD) 1.70V 14. High Voltage DC (HVDC) transmission is mainly used for
A) bulk power transmission over very long distances
C) eliminating reactive power requirement in the operation
B) inter-connecting two systems with the same nominal frequency
D) minimizing harmonics at the converter stations 15. A bipolar junction transistor (BJT) is used as a power control switch by biasing it in the cut-off region (OFF state) or in the saturation region (ON state). In the ON state, for the BJT
A) both the base-emitter and base collector junctions are reverse biased
B) the base-emitter junction is reverse biased, and the base-collector junction is forward biasedC) the base-emitter junction is forward biased, and the base-collector junction is reverse biasedD) both the base-emitter and basecollector junctions are forward biased 16. The Q – meter works on the principle of
A) mutual inductanceB) self inductance
C) series resonanceD) parallel resonance 17. A 800 kV transmission line is having per phase line inductance of 1.1 mH/km and per phase line capacitance of 11.68 nF/km. Ignoring the length of the line, its ideal power transfer capability in MW is
A) 1204 MWB) 1504 MW
C) 2085 MW D) 2606 MW 18. If the following program is executed in a icroprocessor, the number of instruction cycles it will take from START to HALT is
START MVI A, 14H ; Move 14H to register ASHIFT RLC ; Rotate left without carry JNZ SHIFT ; Jump on non-zero to SHIFT
HALTA) 4B) 8
C) 13D) 16
19. A moving iron ammeter produces a full scale torque of 240 uNm with a deflection of 120° at a current of 10 A. The rate of change of self inductance (uH/radian) of the instrument at full scale isA) 2.0 uH/radianB) 4.8 uH/radian
C) 12.0 uH/radianD) 114.6 uH/radian 20. At an industrial sub-station with a 4 MW load, a capacitor of 2 MVAR is installed to maintain the load power factor at 0.97 lagging. If the capacitor goes out of serivce, the load power factor becomes
A) 0.85
B) 1.00
C)0.80 lag D) 0.90 lag 21. The conduction loss versus device current characteristic of a power MOSFET is best approximated by
A) a parabola
B) a straight line
C) a rectangular hyperbola
D) an exponentially decaying function 22. The open loop transfer function of a unity feed back control system is given as G(s) = (as + 1)/s2 . The value of ‘a’ to give a phase margin of 45° is equal to
A) 0.141
B) 0.441
C)0.841
D) 1.141
23. The armature resistance of a permanent magnet dc motor is 0.8 W. At no load, the motor draws 1.5 A from a supply voltage of 25 V and runs at 1500 rpm. The efficiency of the motor while it is operating on load at 1500 rpm drawing a current of 3.5 A from the same source will be
A) 48.0%B) 57.1% C) 59.2%
D) 88.8%
24. A single-phase, 230 V, 50 Hz, 4 pole, capacitor-start induction motor has the following stand-still impedances
Main winding Zm = 6.0 + j4.0 ohms
Auxiliary winding Za = 8.0 + j6.0 ohms,The value of the starting capacitor required to produce 90° phase difference between the currents in the main and auxiliary windings will be
A) 176.84uFB) 187.24 uF
C) 265.26 uF
D) 280.86 uF 25. A single-phase half-controlled rectifier is driving a separately excited dc otor. The dc motor has a back emf constant of 0.5 V/rpm. The armature current is 5 A without any ripple. The armature resistance is 2ohms. The converter is working from a 280 V, single phase ac source with a firing angle of 80°. Under this operating condition, the speed of the motor will be
A) 339 rpmB) 359 rpm
C) 366 rpmD) 386 rpm 26. A 50 Hz, 4-pole, 500 MVA, 22 kV turbo-generator is delivering rated megavolt-amperes at 0.8 power factor. Suddenly a fault occurs reducing is electric power output by 40%. Neglect losses and assume constant power input to the shaft. The accelerating torque in the generator in MNm at the time of the fault will be
A) 1.528 B) 1.018
C) 0.848 D) 0.509 27. The Nyquist plot of loop transfer function G(s) H(s) of a closed loop control system passes through the point (-1, j0) in the G(s) H(s) plane. The phase margin of the system is
A) 0°
B) 45°
C) 90°D) 180° 28. A hydraulic turbine having rated speed of 250 rpm is connected to a synchronous generator. In order to produce power at 50 Hz, the number of poles required in the generator are
A) 6
B) 12
C) 16D) 24 29. For the equation x(t)+3 x(t) +2x(t) = 5, the solution x (t) approaches which of the following values as t tends to infinity ?
A) 0
B) 5
C) 25D) 10
30. The following motor definitely has a permanent magnet rotor
A) DC commutator motor
B) Brushless dc motor
C) Stepper motor D) Reluctance motor
31.The current gain of a bipolar transistor drops at high frequencies because of
A) Transistor capacitances B) High current effects in the base
C) Parasitic inductive elements D) The early effect 32. The simultaneous application of signals x(t) and y(t) to the horizontal and vertical plates, respectively, of an oscilloscope, produces a vertical figure-of-8 display. If P and Q are constants, and x(t) = P sin (4t + 30), then y(t) is equal to
A) Q sin (4t – 30)
B) Q sin (2t + 15)
C) Q sin (8t + 60)D) Q sin (4t + 30)
33. A 500 MW 3-phase Y-connected synchronous generator has a rated voltage of 21.5 kV at 0.85pf. The line current when operating at full load rated conditions ill be
A) 13.43 kA
B) 15.79 kA
C)23.25 kA D) 27.36 kA 34. Total instantaneous power supplied by a 3-phase ac supply to a balanced R-L load is
A) zero
B) constant
C) pulsating with zero averageD) pulsating with non-zero average 35. What are used to increase the range of ammeters.
A) Multipliers
B) Shunts
C) control Springs
D) Potential transformers
36. The number 1000 wouldappear just immediately after
A) FFFF (hex)
B) 1111 (binary)
C) 7777 (octal)
D) All of the above.
37. Among the logic families, the family which can be used at very high frequency greater than 100MHz in a 4 bit synchronous counter isA) TTLASB) CMMOSC) ECLD) TTLLS
38. The frequency is measured byA) Wheatstone bridge
B) hays bridge
C) Owens bridge
D) weins bridge
39. The most commonly used amplifier in sample & hold circuits isa) A unity gain non-inverting amplifier b) A unity gain inverting amplifierc) An inverting amplifier with a gain of 10 d) An inverting amplifiers with a gain of 100
40. Introducing a resistor in the emitter of a common amplifier stabilizes the dc operating point against variations in
a) Only the temperature b) only the β of the transistor
c) Both Temperature & β d) None of the above
ANSWERS ::
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| B | A | B | B | C | B | C | C | C | D |
| 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |
| B | C | B | A | D | C | C | C | B | C |
| 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 |
| A | A | A | A | C | A | D | D | B | C |
| 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 |
| A | B | B | B | B | D | C | D | B | C |
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