1 |
A 50 kW dc shunt motor is loaded to draw rated armature current
at any given speed. When driven
(i) at half the rated speed by armature voltage control and
(ii) at 1.5 times the rated speed by field control, the
respective output powers delivered by the motor are approximately.
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Options |
A) 25kW in (i) and 75kW in (ii) |
B) 25kW in (i) and 50kW in (ii)
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C) 50kW in (i) and 75kW in (ii) |
D) 50kW in (i) and 50kW in (ii) | |
Correct Answer
B 2 |
A fair coin is tossed three times in
succession. If the first toss poduces a head, then the probability
of getting exactly two heads in three tosses is |
Options |
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Correct Answer
D 3 |
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:
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Options |
A) Augmented matrix [Pq] must have the same rank as
matrix P
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B) Vector q must have only non-zero elements
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C) Matrix P must be singular
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D) Matrix P must be square | |
Correct Answer
A 4 |
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
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C) 0.80 lag |
D) 0.90 lag | |
Correct Answer
C 5 |
In the GH(s) plane, the
Nyquist plot of the loop transfer function
G(s)H(s) =
asses through the negative real axis at the point
|
Options |
A) (-0.25, j0) |
B) (-0.5, j0)
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C) (-l, j0) |
D) (-2, j0) | |
Correct Answer
B 6 |
If S =
ò |
¥ |
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x-3 dx, then S has the value |
1 |
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Options |
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Correct Answer
C 7 |
The following motor definitely has a permanent
magnet rotor |
Options |
A) DC commutator motor |
B) Brushless dc motor
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C) Stepper motor |
D) Reluctance motor | |
Correct Answer
C 8 |
The conduction loss versus device current
characteristic of a power MOSFET is best approximated by |
Options |
A) a parabola
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B) a straight line
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C) a rectangular hyperbola
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D) an exponentially decaying function | |
Correct Answer
A 9 |
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 |
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Correct Answer
B 10 |
A 50 Hz, bar primary CT has a secondary with
500 turns. The secondary supplies 5 A current into a purely
resistive burden of l W. The magnetizing ampere-turns is 200. The
phase angle between the primary and secondary current is |
Options |
A) 4.6°
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B) 85.4° |
C) 94.6°
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D) 175.4° | |
Correct Answer
A
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