2. In spring control instruments, controlling torque:
Correct : B. cannot be adjusted easily
3. Chemical effect is used for the operation of:
Correct : C. ampere hour meter
4. The deflection torque can be produced by:
Correct : D. magneitcally
5. Moving coil instruments are:
Correct : D. permanent magnet and dynamometer type
6. For increasing the range of an ammeter, connect:
Correct : C. a low value resistance in parallel with the ammeter coil
7. A galvanometer can be used for measuring current and voltage of a circuit
by:
Correct : C. shunt for measuring current and high resistance in series for voltage
8. The energy consumption of MI instrument as compared to MC instrument is:
Correct : B. more
9. An ammeter requires a change of 4A in its coil to produce a pointer deflection
of 8mm then its sensitivity is
Correct : B. 2.0 mm/a
10. Electrostatic type instruments are mainly used for measurement of
Correct : D. high voltages
11. Measurement range of a voltmeter can be extended by using:
Correct : B. high series resistance
12. Which of the following voltmeter have least power consumption:
Correct : C. electrostatic
13. Which of the following instruments have least torque/weight ratio:
Correct : A. dynamometer type
14. Fluid friction damping can be used in
Correct : B. vertically mounted instruments
15. The ratio and phase angle errors in potential transformer may be reduced by
Correct : D. none of the above
16. A voltmeter should have
Correct : B. . high internal resistance
17. The major advantage of electromagnet type meter over a permanent magnet
meter is
Correct : D. . the electromagnet meter is more rugged
18. The change in the direction of a compass needle, when a current carrying wire
is brought near, is called
Correct : A. . electromagnetic deflection
19. The use of _____ instruments is merely confined within laboratories as
standardizing instruments.
Correct : A. absolute
20. Which of the following instruments indicate the instantaneous value of the
electrical quantity being measured at the time at which it is being measured ?
Correct : B. indicating instruments
21. _____ instruments are those which measure the total quantity of electricity
delivered in a particular time.
Correct : D. integrating
22. Which of the following are integrating instruments ?
Correct : D. ampere-hour and watt-hour meters
23. Which of the following essential features is possessed by an indicating
instrument ?
Correct : D. all of the above
24. A _____ device prevents the oscillation of the moving system and
enables the latter to reach its final position quickly
Correct : C. damping
25. The spring material used in a spring control device should have the
following property.
Correct : D. all of the above
26. Which of the following properties a damping oil must possess ?
Correct : D. all of the above
27. Which of the following devices may be used for extending the range of
instruments ?
Correct : D. all of the above
28. For handling greater currents induction wattmeters are used in
conjunction with
Correct : B. current transformers
29. The pointer of an indicating instrument should be
Correct : A. very light
30. In majority of instruments damping is provided by
Correct : C. eddy currents
31. An ammeter is a
Correct : A. secondary instrument
32. In a portable instrument, the controlling torque is provided by
Correct : A. spring
33. The desirable static characteristics of a measuring system are
Correct : B. accuracy, sensitivity and reproducibility
34. The ratio of maximum displacement deviation to full scale deviation of the
instrument is called
Correct : C. linearity
35. Systematic errors are
Correct : D. all of the above
36. The gravity controlled instrument has crowded scale because current is
proportional to
Correct : C. sine of deflection angle
37. Instrument transformers are
Correct : C. both (a) and (b)
38. The damping force acts on the moving system of an indicating instruments
only when it is
Correct : A. moving
39. A moving iron ammeter coil has few turns of thick
wire in order to have:
Correct : C. low resistance and large current carrying capacity
40. Swamping of resistance is used to compensate error
due to:
Correct : B. temperature variations
41. The turns ratio for C.T. is defined as
Correct : A. n2/n1
42. A 3810/63 P.T. is used with a voltmeter gives reading of 28.11 V , then the
actual line voltage is ------ V
Correct : C. 1700
43. A 1000:5 C.T. is used with an ammeter. If ammeter reading is 1.8 A then the
actual line current is --------------A
Correct : D. 360
44. While testing cables the galvanometer used should be initially short-circuited
in order to protect it from sudden initial inrush currents as the cable have:
Correct : C. a high value of initial capacitance
45. A megger indicates infinity when test terminals are open-circuited. This is
because:
Correct : A. no current flows through the current coil
46. Potentiometer is an __ instrument:
Correct : B. comparison
47. Which of the following bridge is frequency sensitive:
Correct : C. anderson bridge
48. The size of the earth or ground wire is based on the:
Correct : D. both (a) and (c)
49. Earth wire or ground wire is made of:
Correct : D. galvanized steel
50. Average resistance of human body is:
Correct : B. 1000 ohms
51. Generally grounding is provided for:
Correct : C. both (a) and (b)
52. Ground resistance should be designed such that:
Correct : A. grounding resistance should be as low as possible
53. The objective of earthing or grounding is:
Correct : A. to provide as low resistance possible to the ground
54. The vale of resistance of an earthing electrode depends upon
Correct : D. all of the above.
55. A bridge circuit works at a frequency of 2KHz, the following can be used as
detectors for detection of null conditions in the bridge:
Correct : B. headphones and tunable amplifiers.
56. Maxwell’s inductance capacitance bridge is used for measurement of
inductance of:
Correct : B. medium q coils
57. The wheatstone bridge cant be used for precision measurements because
errors are introduce into on account of :
Correct : D. all of the above.
58. High resistances are provided with a guard terminal. This guard terminal is
used to :
Correct : A. bypass leakage current
59. A potentiometer may be used for
Correct : D. all of the above
60. --------- is an instrument which measures the insulation resistance of an
electric circuit relative to earth and one another,
Correct : B. meggar
61. For measuring a very high resistance we should use
Correct : C. meggar
62. The electrical power to a meggar is provided by
Correct : B. permanent magnet d.c. generator
63. In a meggar controlling torque is provided by
Correct : C. coil
64. The operating voltage of a meggar is about
Correct : D. 100 v
65. Which of the following devices should be used for accurate measurement
of low D.C. voltage ?
Correct : B. d.c. potentiometer
66. It is required to measure the true open circuit e.m.f. of a battery. The best
device is
Correct : C. d.c. potentiometer
67. In an Anderson bridge, the unknown inductance is measured in terms of
Correct : B. known capacitance and resistance
68. If the current in a capacitor leads the voltage by 80°, the loss angle of the
capacitor is
Correct : A. 10°
69. To avoid the effect of stray magnetic field in A.C. bridges we can use
Correct : A. magnetic screening
70. Standard resistor is made from
Correct : B. maganin
71. Commonly used standard capacitor is
Correct : B. concentric cylindrical type
72. The most commonly used null deflector in a power
frequency ac bridge is a
Correct : A. vibration galvanometer
73. Loss of charge method is used to measure:
Correct : B. high r
74. Megger is an instrument used for the measurement of:
Correct : A. high resistance and insulation resistance
75. Anderson bridge is used to measure of:
Correct : A. inductance
76. In an electro dynamometer type of wattmeter
Correct : A. the current coil is made fixed
77. In electro dynamometer type of wattmeter current coils designed for carrying
heavy currents use stranded wires or laminated conductors :
Correct : C. to reduce eddy current losses in the conductors
78. In an electro dynamometer type of wattmeter , the inductance of the pressure
coil circuit produces error :
Correct : B. which is higher at low power factors
79. The power in 3ph 4 wire circuit can be measured by using:
Correct : C. three watt meters
80. The resistance in the circuit of the moving coil of a dynamometer wattmeter
should be
Correct : C. high
81. A dynamometer wattmeter can be used for
Correct : A. both d.c. and a.c.
82. The pressure coil of a wattmeter should be connected on the supply side of
the current coil when
Correct : A. load impedance is high
83. In a low power factor wattmeter the pressure coil is connected
Correct : B. to the load side of the current coil
84. In a low power factor wattmeter the compensating coil is connected
Correct : C. in series with pressure coil
85. In a dynamometer 3-phase power factor meter, the planes of the two
moving coils are at
Correct : D. 120°
86. The power factor of a single phase load can be calculated if the
instruments available are
Correct : B. one voltmeter, one ammetqr and one wattmeter
87. The power of a n-phase circuit can be measured by using a minimum of
Correct : A. (n - 1) wattmeter elements
88. A Dynamometer type wattmeter responds to the:
Correct : A. average value of the active power
89. The power measurement in a balanced 3-phase circuit can be done by:
Correct : D. any of the above method
90. The braking torque provided by a permanent magnet in a single phase energy
meter is proportional to the
Correct : D. all of the above.
91. Which of the following is integrating instruments?
Correct : B. energy meter
92. The phenomenon of creeping occurs in
Correct : D. watt-hour meter
93. Hole s are drilled on the opposite sides of the spindle of an energy meter to
avoid
Correct : C. avoid creep on load
94. The pressure coil of an induction type energy meter is
Correct : A. highly inductive
95. Which type of damping is used in Induction type energy meter?
Correct : D. eddycurrent
96. In an Induction type energy meter, maximum torque is obtained when the
parameter of the rotating disc are
Correct : B. x=0
97. An Induction meter meter can handle current upto
Correct : D. 100a
98. In an induction type energy meter, compensation for static friction is
provided by
Correct : C. shading bands
99. Which of the following statements is wrong
Correct : A. there is control spring
100. Which of the following is an essential part of a induction type of meter ?