1. 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 [P q] must have the same rank as matrix P
(b) Vector q must have only non-zero elements
(c) Matrix P must be singular
(d) Matrix P must be square
2. Which three-phase connection can be used in a transformer to introduce a phase
difference of 30° between its output and corresponding input line voltages
(a) Star - Star (b) Star - Delta (c) Delta - Delta (d) Delta - Zigzag
3. The p.u. parameters for a 500 MVA machine on its own base are:
inertia M = 20 p.u.; reactance X = 2 p.u.
The p.u. values of inertia and reactance on 100 MVA common base, respectively,
are
(a) 4, 0.4 (b) 100, 10 (c) 4, 10 (d) 100, 0.4
4. An 800 kV transmission line has a maximum power transfer capacity on the
operated at 400 kV with the series reactance unchanged, the new maximum
power transfer capacity is approximately
P (d) 4
P
(a) P (b) 2P (c) 2
5. The insulation strength of an EHV transmission line is mainly governed by
(a) load power factor (b) switching over-voltages
(c) harmonics (d) corona
6. High Voltage DC (HVDC) transmission is mainly used for
(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
7. The Q-meter works on the principle of
(a) mutual inductance (b) self inductance
(c) series resonance (d) parallel resonance
8. The 8085 assembly language instruction that stores the contents of H and L
registers into the memory locations 2050 and 2051 ,
H H respectively, is:
(a) SPHL 2050H (b) SPHL 2051H (c) SHLD 2050H (d) STAX 2050H
9. A digital-to-analog converter with a full-scale output voltage of 3.5V has a resolution close to 14 mV. Its bit size is:
(a) 4 (b) 8 (c) 16 (d) 32
10. 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
11. A three-phase diode bridge rectifier is fed from a 400V RMS, 50 Hz, three-phase AC source. If the load is purely resistive, the peak instantaneous output voltage is equal to
(a) 400 V (b) 3V (c) 2v d) 200v
12. The output voltage waveform of a three-phase square-wave inverter contains
(a) only even harmonics (b) both odd and even harmonics
(c) only odd harmonics (d) only triplen harmonics
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