Trade Theory Semester 2 JULY 2018
Trade Theory Semester 2 JULY 2018
1. Pimary winding of a tranaformer will be short circuited if-
a) IC supply is applied
b) AC aupply is applied
c) Input impedance is increased
d) All of these
2. The name given to the transformer whose induced secondary voltage is same as the applied primary voltage is________________
a) Auto Transformer
b) Current Transformer
c) Constant Voltage Transformmer
d) Isolation Transformer
3. A transformer is rated in-
a) KW
b) KVAr
c) KVA
d) KV
4. Tapping of a transformer is generally given in-
a) HV side
b) LV side
c) Any side
d) Together HV & LV side
5. Short circuit tool of a transformer determines-
a) Core loss
b) Copper loss
c) Iron loss
d) Hysteresis loss
6. A multiplier for a voltmeter is_______________
a) A high resistance in series with the meter movement
b) A high resistant in parallel with the meter movement
c) Normally less than 1 ohm resistance in series with the meter movement
d) Low resistance in series as well as parallel with meter movement
7. When two inputs of a cathode Ray Oscilloscope are sinusoids of same amplitude 900 out of phase the pattern generated will be-
a) Straight line at 45° with x-axis
b) Of oval shape
c) A Vertical line
d) A circle
8. What is considered as the heart of the Cathode Ray Oscilloscope?
a) Saw-tooth Generator
b) Cathode Ray Tube
c) Horizontal Amplifier
d) Vertical Amplifier
9. In the Y secondary of a transformer the line current Ie at phase current Iph connected as -
a) Ie= Iph
b) Ie = √3 Iph
c) Iph = √3II
d) Ie= 3 Iph
10. ELCB is used for-
a) Open circuit
b) Short circuit
c) Personnel shock
d) All of these
11. A full wave rectifier with capacitor filter is use for-
a) Half wave rectification only
b) Full wave rectification only
c) Rectification and Ripple filtering
d) Any of these
12. In an Analog Multi-meter
a) Resistance
b) Voltage
c) Current
d) All of these
13. The working of
a) MCB.
b) ELCB
c) MCCB
d) Relay
14. If a 10:1 transformer is supplied with 20 V DC, the secondary voltage will be-
a) 2 V DC
b) 2 V AC
c) 200 V DC
d) Zero
15. An induction type measuring instrument is used for measurement of___________ quantities.
a) AC
b) DC
c) Both AC & DC
d) Any of AC or DC
16. The ripple filtering, the following can be used-
a) Inductor
b) Capacity
c) Resistor
d) Transistor
17. The core loss if a transformer may be determined using-
a) Short circuit test
b) Open circuit test
c) Wheatstone bridge
d) All of these
18. A Dynamometer instrument is mainiy used as a/an
a) DC ammeter
b) Wattmeter
c) DC voltmeter
d) Ohmmeter
19. What force in analog instrument quickly brings the moving system to rest in its final position?
a) Damping force
b) Controlling force
c) Deflecting force
d) Force at rest
20. The insulation resistance is measured by____________
a) Ohm meter
b) Insulation meter
c) Megger
d) Wien bridge
21. In Delta/Star transformer of 1:1 turn ratio-
a) Secondary line voltage is greater than primary line voltage
b) Primary line voltage is greater than secondary line voltage
c) Primary line voltage is equal to secondary line voltage
d) All of these
22. 1he starting current of a 220V, 10 HP shunt having an amature resistance of 0.2 ohms, without starter is____________
a) 11 amps
b) 110 amps
c) 1100 amps
d) 11000 amps
23. The relation between voltage and turns of a transform is-
a) v1/v2 = N1/N2
b) v1/v2 = N2/N1
c) v1/v2 = N1L/N12
d) v1/v2 = N1/N2
24. The starting resistance of 3 point starter in D.C motor is connected with_________
a) Parallel across the armature
b) Series with the armature
c) Parallel across the field winding
d) Series with the field winding
25. The flux in the core of a single phase transformer is__________
a) Purely alternating one
b) Purely rotating one
c) Partly altergnating & partly rotating
d) Constant
26. Two things which are same for primary and secondary of a transformer are_________
a) Resistance and leakage reactance
b) Ampere turn and volts per turn
c) Current and induced voltage
d) Number of turns and power
27. A transformer is an efficient device because it
a) Use capacitive coupling
b) Uses inductive coupling
c) Uses electric coupling
d) Is a static device
28. When the secondary of a transformer is short circuited, the primary inductance___________
a) Is decreased
b) Remains the same
c) Is increased
d) Becomes zero
29. FET has-
a) High input impedance
b) Low input impedance
c) Zero impedance
d) None of these
30. The maximum permissible voltage drop in a power industrial circuit should not be more than __________ of the declared supply voltage.
a) 10%
b) 7%
c) 5%
d) 2%
31. The chemical used in a Breather of the transformer is___________
a) Potassium chlorate
b) Silica gel
c) Potassium dichromate
d) Sodium silicate
32. in surface conduit wiring, the saddles should not be fixed at intervals more than ____________ However, where bends or other fittings are used, they should be fixed at the distance of ________ on either side from the center of such fittings.
a) 2.0m, 80 cm
b) 1.8m, 70 cm
c) 1.2 m, 30 cm
d) 1.5 m, 50 cm
33. While testing the wiring installation with MEGGAR, the most important precaution to be taken in to ___________
a) Switch OFF the mains power supply
b) Switch ON the mains power supply
c) Keep all the live, neutral & earth wires should be shorted together
d) Keep all the live, neutral & earth connections opened
34. The device which works on the excessive oil vapors in a transformer tank and it cuts off the transformer fiom circuit as soon as the fault occurs is___________
a) Air break switch
b) Gas filled thermostate
c) Buchholz Relay
d) Reed Reiay
35. Panch through IGBTS have Time.
a) Slow Turn OFF
b) Slow Turn ON
c) Stable Turn ON
d) Faster Turn OFF
36. The percetage change in output voltage from no-load to full-load is termed as the___________ of the transformer.
a) Efficiency
b) Voltage Regulation
c) Tum Ratio
d) Copper Losses
37. The sensitivity of a moving coil voltmeter is defined as
a) Ohms Volt
b) Ohms volt
c) Volt Ampere
d) Vol/Ohm
38. The function of the __________ is to maintain the oil level in the transformer tank as the oil expands or contracts.
a) Breather
b) Explosion vent
c) Conservator
d) Tap changer
39. When both deflecting controlling torque act,and balance, the pointer of an indicating instrument comes to-
a) Mid position
b) Maximum position
c) Three fourth position
d) Rest
40. PMMC instrument is used for-
a) DC measurement
b) ACMeasurement
c) Both AC/DC measurement
d) Calibration
41. The anode mud in a cell is collected-
a) Below anode rod
b) Below cathode rod
c) On anode rod
d) On cathode rod
42.7he direction of rotation of a D.C. motor is determined by_____________
a) Fleming's right hand rule
b) Fleming's left hand rule
c) Ampere's right hand grip rule
d) Maxwell's cork screw rule
43. A light fan sub circuit can accommodate of maximum load of-
a) 100 W
b) 500 W
c) 800 W
d) 1 KW
44. The primary and secondary windings of a transformer are_________
a) Conductively Linked
b) Inductively Linked
c) Not at all linked
d) Electrically Linked
45. The size of a conductor used in power cables depends on the___________
a) Operating voltage
b) Type of insulation used
c) Power factor
d) Current to be carried
46. As per IE rules, the minimum size of copper conductor used in domestic wiring must not be of the size less than__________
a) 1/1.12 mm
b) 1/1.01 mm
c) 1/0.75 mm
d) 1/0.50 mm
47. PVC stands for-
a) Poly variable conductors
b) Poly vinyl chloride
c) Pre verified conductors
d) Poly voltage chloride
48. Isolation of heating coil from metallic body in an electric iron is carried out using-
a) Varnish
b) PVC coating
c) Mica film
d) Porcelain
49. One of the main advantages of__________ of wiring is that, all the joints are at the swithhes and lamps/fans which are accessible for inspection in case of faults.
a) Tree system
b) Joint Box or Tee system
c) Loop-in system
d) Both (a) & (b)
50. No steel conduit of less than ________ in diameter should be used in wiring system.
a) 12.7 mm
b) 11.2 mm
c) 10.5 mm
d) 9.7 mm