TECHNICAL PAPER-40 QUESTION,
(1)in a ckt. We r giving voltage of 50 Hz as well as 60. then what will be the
(a)less than 50 (b)more than 60(c)in between 50 & 60
(d)none..........according to our conclusion answer will be none because if we
apply two frequency component resultant frequency we can not say with such an
ease. You should confirm the answer
2.In a ckt a single resistor is connected across a d.c. source, what will be the
effect on current in first resistor if we connect one more resistance in
parallel with earlier one....
Answer.. no change since it is a parallel combination.
3.why we don't like flashover in transmission line (t-line)- (a ) it may create
earth fault(b )it reduces the life of insulator.....
Read something about flashover & puncture.
4.total no of strands in a acsr conductor is 81, then what is the no. of
conductor in its outer layer....(a)36 (b)18 (c)24.......Also read some more on
5.Two questions based on p.u. calculation like , p.u. calculation is given with
respect to some old base and u have to calculate it with reference to new base.
(new resistance/old)=(mva new /mva old)*(old voltage/new voltage)2.
Other question is based upon transfer of p.u calculation in transformer i.e. how
base changes when we we move from primary to secondary or like wise.read some
more on p.u calculation.
6.which table is referred for sag calculation-
7.in a R-L ckt a ac voltage is applied , such that instantaneous power is
negative for 2ms, then what will be the power factor.
(a) 9 deg, (b) 18 deg, (c) 36 Deg...........(I don't know the correct ans)
8. In an incandescent lamp
(a) luminous intensity is more than non-luminous intensity
(b) ,, ,, ,, less ,, ,, ,,
Ans: Since efficiency is less than 100%, hence ans is (b), u should confirm
9. In which motor no-load to full-load diff. is lowest
(a) series motor, (b) shunt motor, (c) Compound motor
10. In a 60Hz induction motor full load speed is 850 rpm then what is the
Synchronous speed. (a) 900 rpm, (b) 950 rpm, (c) 1600
11. A sync. Motor is running at synch. Speed, if al of sudden D.C. excitation is
(a) it will rotate at slip speed, (b) it will stop, (c) it will continue to
rotate at sync. Speed
Ans: (a), because actually it will acts as Induction motor.
12. A transmission line is designed for 50Hz, 440KV. If we want to transfer
power at 60Hz, 440 KV, then the power transfer capability will
(a) decrease, (b) Increase, (c)None
Ans: (a) ...as P=( |Vt| |Ef| sin (delta) ) / X, where (delta) is torque
13. Increased rotor resistance in rotor ckt of induction motor is related with
(a) high starting torque, (b) more speed variation,.....................Ans:
14. In the formulae E = 4.44 f N Ô, Ô is
(a) Avg value, (b) Rms value, (c) Maximum value.....................Ans:
15. Voltage & current in a ckt is given by V= V1+j V2 and I= I1 +j I2, then rms
.......(refer book by Edministrator on NETWORK ..)
16. Input impedence of MOSFET is
(a) more than BJT........(Ans)
17, 18. Remember truth table of AND, NOR, NAND, OR, EX-OR ETC...
19. Conversion of Binary number into Equivalent decimal No.
20. Megger is used for the measurement of (a) Insulation resistance, (b)
Conductor resistance.............Ans: (a)
21. Form factor for sinusoidal as well as DC
22. Formulae of Regulation (Vs- Vr)* 100/ Vr, then transmission line is
(a) short transmission line, (b) long, (c) medium...................Ans: (a)
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