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ECE :: Measurements and Instrumentation

  1. Which bridge can be used to measure frequency?

  2. A.
    Maxwell
    B.
    Kelvin
    C.
    Schering
    D.
    Wein

  3. The time base generator in a CRO gives an output which is

  4. A.
    low frequency sinusoidal
    B.
    high frequency sinusoidal
    C.
    low frequency rectangular
    D.
    high frequency sawtooth

  5. The standard deviation σ in terms of n observations having deviations from mean dm can be written as


  6. An average responding rectifier type electronic voltmeter has its scale calibrated in terms of rms value of sine wave. If 100 V peak value square wave is fed to this voltmeter, the reading will be

  7. A.
    111 V
    B.
    100 V
    C.
    90.9 V
    D.
    70.7 V

  8. In low power factor wattmeter, the compensating coil is connected

  9. A.
    in series with current coil
    B.
    in parallel with current coil
    C.
    in series with pressure coil
    D.
    in parallel with pressure coil

  10. A permanent magnet moving coil measures

  11. A.
    true rms value
    B.
    dc value
    C.
    peak value
    D.
    rms plus dc value

  12. A CT is used to feed current coils of wattmeter, energy meter, power factor meter and an ammeter. Then

  13. A.
    all the coils are in series
    B.
    all coils are in parallel
    C.
    the coils are in series-parallel
    D.
    either (a) or (b)

  14. In measurements using strain gauge, the dummy strain gauge is used to

  15. A.
    compensate for resistance of strain gauge
    B.
    compensate for change in temperature
    C.
    compensate for error due to change in voltage of battery
    D.
    compensate for error in voltmeter

  16. In an ac single phase energy meter, the potential coil is put on

  17. A.
    both side limbs, of upper magnet
    B.
    central limb of upper magnet
    C.
    one side limb of upper magnet
    D.
    either (a) or (b)

  18. The chemical effect of current is used in

  19. A.
    dc ampere hour meter
    B.
    dc ammeter
    C.
    ac energy meter
    D.
    all of the above