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ECE :: Measurements and Instrumentation

  1. A current of 3.25 A is flowing through a resistance of 34.98 Ω. The voltage drop across resistance to the appropriate number of significant figures is

  2. A.
    113.685 V
    B.
    113.68 V
    C.
    113.6 V
    D.
    114 V

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  3. The braking torque in single phase energy meter is proportional to speed of disc.

  4. A.
    True
    B.
    False

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  5. To measure a resistance by a dc potentiometer

  6. A.
    it is necessary to standardise the potentiometer
    B.
    it is not necessary to standardise the potentiometer
    C.
    it is necessary to use a volt ratio box
    D.
    none of the above

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  7. In dc tacho generators used for measurement of speed of shaft, frequent calibration is necessary because

  8. A.
    contacts wear off
    B.
    strength of permanent magnet decreases with age
    C.
    armature current produces heating effect
    D.
    there is back emf

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  9. A multimeter can be used as ohmmeter.

  10. A.
    True
    B.
    False

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  11. A voltage of about 200 V dc can be measured

  12. A.
    directly by dc potentiometer
    B.
    by dc potentiometer in conjunction with a volt ratio box
    C.
    a dc potentiometer in conjunction with a known resistance
    D.
    both (b) and (c)

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  13. In a low power factor wattmeter, compensation for pressure coil current is provided.

  14. A.
    True
    B.
    False

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  15. De Sauty bridge is very widely used due to

  16. A.
    simplicity
    B.
    perfect balance for imperfect capacitor
    C.
    perfect balance for air capacitors
    D.
    maximum sensitivity

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  17. A Weston synchronoscope is a

  18. A.
    moving coils instrument
    B.
    moving iron instrument
    C.
    dynamometer instrument
    D.
    induction instrument

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  19. In a dynamometer 3 phase power factor meter, the planes of the two moving coils are at

  20. A.
    60°
    B.
    C.
    120°
    D.
    90°

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