| No. | Question |
| 1 |
For the scalar field u =
+
, magnitude of the gradient at the point (1,3) is |
| Options |
|
| Correct Answer |
C |
| |
| 2 |
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 |
| Options |
|
| Correct Answer |
B |
| |
| 3 |
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 current is 5 A without any ripple. The armature resistance is 2W. 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 |
| Options |
| A) 339 rpm |
B) 359 rpm |
| C) 366 rpm |
D) 386 rpm |
|
| Correct Answer |
C |
|
| |
| 4 |
In relation to the synchronous machines, which one of the following statements is false? |
| Options |
| 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 start |
C) 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 |
|
| Correct Answer |
C |
| |
| 5 |
The 8085 assembly language instruction that stores the content of H and L registers into the memory locations 2050H and 2051H, respectively, is
|
| Options |
| A) SPHL 2050H |
B) SPHL2051H |
| C) SHLD 2050H |
D) STAX 2050H
|
|
| Correct Answer |
C |
| |
| 6 |
If
is the electric field intensity, Ñ(Ñ x
) is equal to |
| Options |
| A)
|
B) |
| |
| C) null vector |
D) zero |
|
| Correct Answer |
D |
| |
| 7 |
For the function f(x) = x2 e-x, the maximum occurs when x is equal to |
| Options |
|
| Correct Answer |
B |
| |
| 8 |
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 powere and the power factor, respectively, are |
| Options |
| A) 13.0 kW, 0.334 |
B) 13.0 kW, 0.684
|
| C) 8.0 kW, 0.52 |
D) 8.0 kW, 0.334 |
|
| Correct Answer |
D |
| |
| 9 |
The insulation strength of an EHV transmission line is mainly governed by |
| Options |
| A) load power factor |
B) switching over-voltages
|
| C) harmonics |
D) corona |
|
| Correct Answer |
B |
| |
| 10 |
For the equation,
s3 - 4s2+ s + 6 = 0
the number of roots in the left half of s-plane will be |
| Options |
| A) zero |
B) one
|
| C) two |
D) three
|
|
| Correct Answer |
C |
| |
| 11 |
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 |
| Options |
| A) 1.00V |
B) 1.34V
|
| C) 1.50V |
D) 1.70V
|
|
| Correct Answer |
B |
| |
| 12 |
High Voltage DC (HVDC) transmission is mainly used for
|
| Options |
A) bulk power transmission over very long distances
|
B) inter-connecting two systems with the same nominal frequency |
| C) eliminating reactive power requirement in the operation |
D) minimizing harmonics at the converter stations
|
|
| Correct Answer |
A |
| |
| 13 |
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 |
| Options |
| 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 biased |
| C)
the base-emitter junction is forward biased, and the base-collector junction is reverse biased
|
D) both the base-emitter and base-collector junctions are forward biased |
|
| Correct Answer |
D |
| |
| 14 |
The Q - meter works on the principle of |
| Options |
| A) mutual inductance |
B) self inductance
|
| C) series resonance |
D) parallel resonance |
|
| Correct Answer |
C |
| |
| 15 |
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 |
| Options |
| A) 1204 MW |
B) 1504 MW |
| C) 2085 MW |
D) 2606 MW |
|
| Correct Answer |
C |
| |
| 16 |
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 A
SHIFT RLC ; Rotate left without carry
JNZ SHIFT ; Jump on non-zero to SHIFT
HALT |
|
| Options |
|
| Correct Answer |
C |
| |
| 17 |
A moving iron ammeter produces a full scale torque of 240 mNm with a deflection of 120° at a current of 10 A. The rate of change of self inductance (mH/radian) of the instrument at full scale is |
| Options |
| A) 2.0 mH/radian |
B) 4.8 mH/radian |
| C) 12.0 mH/radian |
D) 114.6 mH/radian |
|
| Correct Answer |
B |
| |
| 18 |
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 |
| Options |
| A) 0.85 |
B) 1.00
|
| C) 0.80 lag |
D) 0.90 lag |
|
| Correct Answer |
C |
| |
| 19 |
The conduction loss versus device current characteristic of a power MOSFET is best approximated by |
| Options |
A) a parabola
|
B) a straight line
|
C) a rectangular hyperbola
|
D) an exponentially decaying function |
|
| Correct Answer |
A |
| |
| 20 |
If P and Q are two random events, then the following is TRUE
|
| Options |
A) Independence of P and Q implies that probability (P  Q ) = 0
|
B) Probability (P  Q )  Probability (P) + Probability (Q)
|
C) If P and Q are mutually exclusive, then they must be independent
|
D) Probability (P Q )  Probability (P)
|
|
| Correct Answer |
D |