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Home Chemical Engineering Process Control and Instrumentation Comments

  • Question
  • Stabilising time for the controllers is the time required for the response to reach __________ percent of its ultimate value.


  • Options
  • A. 63.2
  • B. 87.5
  • C. 95
  • D. 100

  • Correct Answer
  • 95 


  • Process Control and Instrumentation problems


    Search Results


    • 1. Temperature measurement by optical pyrometer is done above __________ point, which is 1063°C.

    • Options
    • A. antimony
    • B. gold
    • C. silver
    • D. nickel
    • Discuss
    • 2. Vapour actuated pressure spring thermometer does not require ambient temperature compensation. Ambient temperature compensation is provided in gas or liquid expansion pressure spring thermometer by

    • Options
    • A. making the volume of thermometer bulb as large as conveniently possible.
    • B. reducing the volume of the capillary to a minimum.
    • C. reducing the volume of the receiving element to a minimum.
    • D. all 'a', 'b' & 'c'.
    • Discuss
    • 3. When a bare thermocouple is covered by a protective sheath, the response becomes

    • Options
    • A. faster and oscillatory.
    • B. faster and non-oscillatory.
    • C. slower and oscillatory.
    • D. slower and non-oscillatory.
    • Discuss
    • 4. Stability of a control system containing a transportation lag can be best analysed by

    • Options
    • A. Routh test
    • B. root locus methods
    • C. frequency response methods
    • D. none of these
    • Discuss
    • 5. The transfer function of a process is . If a step change is introduced into the system, then the response will be

    • Options
    • A. under damped
    • B. critically damped
    • C. over damped
    • D. none of these
    • Discuss
    • 6. Working principle of mercury in glass thermometer is based on the __________ of mercury with increase in temperature.

    • Options
    • A. increase of pressure
    • B. increase of thermal conductivity
    • C. volumetric expansion
    • D. differential linear expansion
    • Discuss
    • 7. The open loop transfer function of a process is . In the root locus diagram, the poles will be at

    • Options
    • A. -1, -4
    • B. 1, 4
    • C. -2, -3
    • D. 2, 3
    • Discuss
    • 8. Composition of alloys can be determined by

    • Options
    • A. polarograph
    • B. chromatograph
    • C. refractrometer
    • D. none of these
    • Discuss
    • 9. A constant volume gas thermometer employing __________ is used to measure sub-zero (i.e., < 0° C) temperature.

    • Options
    • A. helium
    • B. hydrogen
    • C. nitrogen
    • D. none of these
    • Discuss
    • 10. A mercury thermometer can not be used to measure the temperature below the freezing point of mercury, which is __________ °C.

    • Options
    • A. -38.9
    • B. -11.9
    • C. -60.9
    • D. -80.9
    • Discuss


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