1. Mho relay is usually employed for the protection of
a) Short lines only
b) Medium lines only
c) Long lines only
d) Any line
Ans: Long lines only

2. A modern power semiconductor device IGBT is combines the characteristics of
a) BJT and MOSFET
b) FCT and GTO
c) SCR and MOSFET
d) SCR and BJT
Ans: BJT and MOSFET

3. For a single-phase a.c. to d.c. controlled rectifier to operate in regenerative mode, which of the following conditions should be satisfied?
a) Half –controlled bridge, a < 90°, source of e.m.f. in load b) Half-controlled bridge, a > 90°, source of e.m.f. in load
c) Full-controlled bridge, a > 90°, source of e.m.f. in load
d) Full-controlled bridge, a < 90°, source of e.m.f. in load

 Ans: Full-controlled bridge, a > 90°, source of e.m.f. in load

4. Which is the most suitable power device for high frequency ( more 100 kHz) switching application?
a) Power MOSFET
b) BJT
c) SCR
d) UJT
Ans: Power MOSFET

5. In a thyristor Latching current is ________ than Holding current
a) Equal
b) Less
c) Greater
d) None
Ans: Greater

6. The transfer function of a system is 10/(1+s) when operating as a unity feedback system, the steady state error to a step input will be
a) 0
b) 1/11
c) 10
d) Infinity
Ans: 1/11

7. Which one of the following statements for a dc machine which is provided with inter pole winding (IW) as well as compensating winding (CW) is correct
a) Both IW and CW are connected in series with Armature winding
b) Both IW and CW are connected in parallel with Armature winding
c) IW connected in series but CW is connected in parallel with Armature winding
d) CW connected in series but IW is connected in parallel with Armature winding
Ans: Both IW and CW are connected in series with Armature winding

8. A 0-10 mA PMMC ammeter reads 5mA in a circuit; its bottom control spring snaps out suddenly the meter will now read.
a) 5mA
b) 10mA
c) 2.5mA
d) 0
Ans: 0

9. A dc cumulatively compounded motor delivers rated load torque at rated speed. If series field is short circuited, then the armature current and speed will
a) Both increases
b) Both decreases
c) Increases and decreases
d) Decreases and increases
Ans: Both increases

10. Moving coil in dynamometer wattmeter connected
a) In series with fixed coil
b) Across supply
c) In series with load
d) Across load
Ans: Across supply

11. Temperature of electrode in Arc furnace is
a) 1000 deg
b) 1500 deg
c) 1500 deg to 3500 deg
d) 4500 deg

12. In bode plot the point which separates the lower and upper frequencies is called
a) Critical point
b) Cut-off point

13. Nyquest stability is used to determine
a) Absolute Stability
b) Relative Stability
c) Both
d) None
Ans: Both*

14. When 220V dc shunt alternator generating the voltage at rated value. If direction of rotation is reversed, then alternator will
a) Build up its voltage with same polarity
b) Build up its voltage with opposite polarity
c) No build up of voltage
d) None
Ans: No build up of voltage

15. Over lap Angle depends on_________
a) Load inductance
b) Loa capacitance
c) Source inductance
d) Source capacitance
Ans: Source inductance

16. Area under speed time curve gives
a) Time
b) Speed
c) Distance
d) None
Ans: Distance

17. The regulation of Short Transmission lines depends up on
a) Distance of line
b) Frequency
c) Power factor
d) All
Ans: Power factor

18. Which of the following plant is having lowest load factor?
a) Diesel Plant
b) Pumped storage Plant
c) Thermal Plant
d) Nuclear Plant
Ans: Diesel Plan

19. For SR latch whent the out put is undesirable
a) 0, 0
b) 1, 0
c) 0, 1
d) 1, 1
Ans: 1, 1

20. For interrupting capacitive currents which Circuit Breaker (CB) is used
a) SF6 CB
b) Oil CB
c) Vacuum CB
d) Air blast CB
Ans: Vacuum CB

21. Heat convection, radiation, and conduction all are takes place in
a) Ice
b) Boiler
c) Refrigerator
d) Flue gases in pipe
Ans:

22. When moving iron meter is used to measure d.c current what is the disadvantage
a) It calibration in rms value
Ans: It calibration in rms value

23. When maximum power transfer to load is
a) 20 W
b) 50 W
c) 100W
d) 0W
Ans: 0W

24. Find Zbus Parameters
a) Z11=Z12=Z21= j0.1 ohm, Z22=j0.3 ohm
Ans: Z11=Z12=Z21= j0.1 ohm, Z22=j0.3 ohm

25. Find Z11 and Z12
a) Z11=4 ohm, Z12= 2 ohm
b) Z11=4 ohm, Z12= 5 ohm
c) Z11=5 ohm, Z12= 2 ohm
d) Z11=4 ohm, Z12= 3 ohm

26. Current in 5 ohm resister is
a) 10 A
b) -10 A
c) 5 A
d) -5 A
Ans: -10 A

27. Find I in the circuit at t=0+
a) 2 A b) 5 A
c) 7 A d) 10 A
Ans:

28. Find voltage across inductor at t=0+
a) 0 V
b) 2.5 V
c) 5 V
d) 10 V
Ans: 5 V

29. This wave is applied to the PMMC meter, meter reads
a) 0 V
b) 3 V
c) 2 V
d) 1 V
Ans: 1 V

30. Find Vab a) Zero
b) 50 at an angle of 90 deg
c) 50 at an angle of 90 deg
d) None

31. Find E in the circuit
a) 5 V
b) 10 V
c) 20 V
d) None
Ans: None

32. Vab is reference then angle between Vab and Ib is
a) -15 deg
b) 240 deg
c) 180 deg
d) -45 deg
Ans: -15 deg*

33. When maximum power transfer to load is
Click Here to Show Diagram
a) 20 W
b) 50 W
c) 100W
d) 0W
Ans: 0W

34. Find Zbus Parameters
Click Here to Show Diagram
a) Z11=Z12=Z21= j0.1 ohm, Z22=j0.3 ohm
Ans: Z11=Z12=Z21= j0.1 ohm, Z22=j0.3 ohm

35. Find Z11 and Z12
Click Here to Show Diagram
a) Z11=4 ohm, Z12= 2 ohm
b) Z11=4 ohm, Z12= 5 ohm
c) Z11=5 ohm, Z12= 2 ohm
d) Z11=4 ohm, Z12= 3 ohm
Ans:

36. Current in 5 ohm resister is
Click Here to Show Diagram
a) 10 A
b) -10 A
c) 5 A
d) -5 A
Ans: -10 A

37. Find I in the circuit at t=0+
Click Here to Show Diagram
a) 2 A
b) 5 A
c) 7 A
d) 10 A
Ans: 2 A

38. Find voltage across inductor at t=0+
Click Here to Show Diagram
a) 0 V
b) 2.5 V
c) 5 V
d) 10 V
Ans: 5 V

39. This wave is applied to the PMMC meter, meter reads
Click Here to Show Diagram
a) 0 V
b) 3 V
c) 2 V
d) 1 V
Ans: 1 V

40. Find Vab
Click Here to Show Diagram
a) Zero
b) 50 at an angle of 90 deg
c) 50 at an angle of 90 deg
d) None
Ans:

41. Find E in the circuit
Click Here to Show Diagram
a) 5 V
b) 10 V
c) 20 V
d) None

Ans: None

42. Vab is reference then angle between Vab and Ib is
Click Here to Show Diagram
a) -15 deg
b) 240 deg
c) 180 deg
d) -45 deg

Ans: -15 deg*