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ECE :: Measurements and Instrumentation

  1. To measure an emf by dc potentiometer it is necessary to standardise the potentiometer with the help of a standard cell.

  2. A.
    True
    B.
    False

  3. Which of the following transformers has low primary current?

  4. A.
    Current transformer
    B.
    Potential transformer
    C.
    Distribution transformer
    D.
    Both (a) and (b)

  5. The phenomenon of creep occurs in

  6. A.
    energy meters
    B.
    voltmeters
    C.
    ammeters
    D.
    wattmeters

  7. A D' Arsonval galvanometer is a

  8. A.
    moving coil instrument
    B.
    moving iron instrument
    C.
    dynamometer instrument
    D.
    induction instrument

  9. Schering bridge is used to measure

  10. A.
    capacitance and dielectric loss
    B.
    inductance
    C.
    resistance
    D.
    mutual inductance

  11. In a CRO the Y plates are oriented

  12. A.
    horizontally
    B.
    vertically
    C.
    at an angle of 20° of horizontal
    D.
    at an angle of 70° of horizontal

  13. The accuracy of an instrument is determined by

  14. A.
    closeness of indicated value to the actual value
    B.
    repeatability of measured value
    C.
    speed with which the reading approaches final value
    D.
    least value which can be measured

  15. If σ standard deviation, probable error

  16. A.
    σ
    B.
    ± 1.19 σ
    C.
    ± 0.6745 σ
    D.
    ± 0.4125 σ

  17. Assertion (A): In two wattmeter method of 3 phase power measurement, one of the wattmeters would read negative if power factor of load is less than 0.5.

    Reason (R): In two wattmeter method of 3 phase power measurement, both the wattmeters would show equal readings if power factor of load is unity.

  18. A.
    Both A and R are true and R is correct explanation of A
    B.
    Both A and R are true but R is not correct explanation of A
    C.
    A is true R is false
    D.
    A is false R is true

  19. In a megger the moving coil meter has a permanent magnet.

  20. A.
    True
    B.
    False