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ECE :: Measurements and Instrumentation

  1. Two resistances R1 = 18.7 Ω. and R2 = 3.624 Ω in series. The total resistance to the appropriate number of significant figures is

  2. A.
    22.324 Ω
    B.
    22.32 Ω
    C.
    22.3 Ω
    D.
    22 Ω

  3. The input impedance of CRO is about

  4. A.
    zero
    B.
    10 Ω
    C.
    100 Ω
    D.
    one mega ohm

  5. Which of the following is not correct in respect of electrostatic instrument?

  6. A.
    It is essentially a voltmeter
    B.
    It is suitable for only high voltages
    C.
    It has a uniform scale
    D.
    It can be used for both ac and dc

  7. The wave applied to X plates, for ohtaining trace of voltage wave, is

  8. A.
    sawtooth wave
    B.
    sinusoidal wave
    C.
    rectangular wave
    D.
    either (a) or (c)

  9. The response of a thermistor overs the whole of its temperatures range is

  10. A.
    linear
    B.
    non-linear
    C.
    almost linear
    D.
    either (a) or (c)

  11. A resistance is measured by voltmeter-ammeter method. The voltmeter is 0-250V, ± 1% accuracy and ammeter is 0-5 A, ± 1 % accuracy. The readings of voltmeter and ammeter are 100 V and 2 A respectively. The error in the measured resistance can be

  12. A.
    ± 1%
    B.
    ± 2%
    C.
    ± 5%
    D.
    ± 10%

  13. It is required to study transients during switching process. Which CRO should be preferred?

  14. A.
    Ordinary CRO
    B.
    Dual beam CRO
    C.
    Dual trace CRO
    D.
    Storage oscilloscope

  15. Assertion (A): In loss of charge method, it is preferable to use an electronic voltmeter.

    Reason (R): The resistance of electronic voltmeter is very high.

  16. 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

  17. If the secondary winding of CT is opened when primary coil is carrying current

  18. A.
    transformer will burn immediately
    B.
    there will be weak flux density in core
    C.
    there will be very high induced voltage in secondary
    D.
    there will be high current in secondary

  19. The percentage limiting error in an instrument reading 8.3 V and having guaranteed accuracy of 1% of the full scale reading and range of 0-150 V is

  20. A.
    1.81%
    B.
    0.181%
    C.
    18.1%
    D.
    0.0018%