26. An ammeter is a
(a) secondary instrument
(b) absolute instrument
(c) recording instrument
(d) integrating instrument
Ans: a
27. In a portable instrument, the controlling torque is provided by
(a) spring
(b) gravity
(c) eddy currents
(d) all of the above
Ans: a
28. The disc of an instrument using eddy current damping should be of
(a) conducting and magnetic material
(b) non-conducting and magnetic material
(c) conducting and non-magnetic material
(d) none of the above
Ans: c
29. The switch board instruments
(a) should be mounted in vertical position
(6) should be mounted in horizontal position
(c) either (a) or (b)
(d) neither (a) nor (b)
Ans: a
30. The function of shunt in an ammeter is to
(a) by pass the current
(b) increase the sensitivity of the ammeter
(c) increase the resistance of ammeter
(d) none of the above
Ans: a
31. The multiplier and the meter coil in a voltmeter are in
(a) series
(b) parallel
(c) series-parallel
(d) none of the above
Ans: a
32. A moving iron instrument can be used for
(a) D.C. only
(b) A.C. only
(c) both D.C. and A.C.
Ans: c
33. The scale of a rectifier instrument is
(a) linear
(b) non-linear
(c) either (a) or (b)
(d) neither (a) nor (b)
Ans: a
34. For measuring current at high frequency we should use
(a) moving iron instrument
(b) electrostatic instrument
(c) thermocouple instrument
(d) none of the above
Ans: c
35. The resistance in the circuit of the moving coil of a dynamometer wattmeter should be
(a) almost zero
(b) low
(c) high
(d) none of the above
Ans: c
36. A dynamometer wattmeter can be used for
(a) both D.C. and A.C.
(b) D.C. only
(c) A.C. only
(d) any of the above
Ans: a
37. An induction wattmeter can be used for
(a) both D.C. and A.C.
(6) D.C. only
(c) A.C. only
(d) any of the above
Ans: C
38. The pressure coil of a wattmeter should be connected on the supply side of the current coil when
(a) load impedance is high
(b) load impedance is low
(c) supply voltage is low
(d) none of the above
Ans: a
39. In a low power factor wattmeter the pressure coil is connected
(a) to the supply side of the current coil
(b) to the load side of the current coil
(c) in any of the two meters at connection
(d) none of the above
Ans: b
40. In a low power factor wattmeter the compensating coil is connected
(a) in series with current coil
(b) in parallel with current coil
(c) in series with pressure coil
(d) in parallel with pressure coil
Ans: c
41. In a 3-phase power measurement by two wattmeter method, both the watt meters had identical readings. The power factor of the load was
(a) unity
(6) 0.8 lagging
(c) 0.8 leading
(d) zero
Ans: a
42. In a 3-phase power measurement by two wattmeter method the reading of one of the wattmeter was zero. The power factor of the load must be
(a) unity
(b) 0.5
(c) 0.3
(d) zero
Ans: b
43. The adjustment of position of shading bands, in an energy meter is done to provide
(a) friction compensation
(b) creep compensation
(c) braking torque
(d) none of the above
Ans: a
44. An ohmmeter is a
(a) moving iron instrument
(b) moving coil instrument
(c) dynamometer instrument
(d) none of the above
Ans: b
45. When a capacitor was connected to the terminal of ohmmeter, the pointer indicated a low resistance initially and then slowly came to infinity position. This shows that capacitor is
(a) short-circuited
(b) all right
(c) faulty
Ans: b
46. For measuring a very high resistance we should use
(a) Kelvin’s double bridge
(b) Wheat stone bridge
(c) Meggar
(d) None of the above
Ans: c
47. The electrical power to a meggar is provided by
(a) battery
(b) permanent magnet D.C. generator
(c) AC. generator
(d) any of the above
Ans: b
48. In a meggar controlling torque is provided by
(a) spring
(b) gravity
(c) coil
(d) eddy current
Ans: c
49. The operating voltage of a meggar is about
(a) 6 V
(b) 12 V
(c) 40 V
(d) 100 V
Ans: d
50. Murray loop test can be used for location of
(a) ground fault on a cable
(b) short circuit fault on a cable
(c) both the ground fault and the short-circuit fault
(d) none of the above
Ans: c