| 1 |
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 |
| Options |
| A) 48.0% |
B) 57.1%
|
| C) 59.2% |
D) 88.8% |
|
|
|
| Correct Answer |
A |
|
| 2 |
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 |
|
| 3 |
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 |
|
| 4 |
The Q - meter works on the principle of |
| Options |
| A) mutual inductance |
B) self inductance
|
| C) series resonance |
D) parallel resonance |
|
|
|
| Correct Answer |
C |
|
| 5 |
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 |
|
| 6 |
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 |
|
| 7 |
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 |
|
| 8 |
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 |
|
| 9 |
The output voltage waveform of a three-phase
square-wave inverter contains |
| Options |
| A) only even harmonics |
B) both odd and even harmonics |
| C) only odd harmonics |
D) only triplen harmonics
|
|
|
|
| Correct Answer |
C |
|
| 10 |
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)
|
|
|
|