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Home Chemical Engineering Process Control and Instrumentation Comments

  • Question
  • 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

  • Correct Answer
  • -38.9 


  • Process Control and Instrumentation problems


    Search Results


    • 1. 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
    • 2. Composition of alloys can be determined by

    • Options
    • A. polarograph
    • B. chromatograph
    • C. refractrometer
    • D. none of these
    • Discuss
    • 3. 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
    • 4. 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
    • 5. 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
    • Discuss
    • 6. Emf developed by a thermocouple while measuring a temperature of 400°C is 22 mV. The type of thermocouple used is

    • Options
    • A. chromel-alumel
    • B. iron-constantan
    • C. platinum-rhodium
    • D. platinum-platinum+rhyodium
    • Discuss
    • 7. Routh stability method uses __________ loop transfer function.

    • Options
    • A. open
    • B. closed
    • C. either (a) or (b)
    • D. neither (a) nor (b)
    • Discuss
    • 8. Time constant is the

    • Options
    • A. time taken by the controlled variable to reach 63.2% of its full change.
    • B. same as transportation lag.
    • C. same as dead time.
    • D. time required by the measured variable to reach 63.2% of its ultimate change.
    • Discuss
    • 9. Specific conductance is defined as the reciprocal of resistance in ohms of 1c.c. of liquid at a specified temperature. Its value for distilled water is about __________ micro mho/cm3.

    • Options
    • A. 50
    • B. 100
    • C. 10
    • D. 1
    • Discuss
    • 10. Thermal conductivity measurement is used for the determination of

    • Options
    • A. O2 percentage in the flue gas.
    • B. specific gravity of petrofuels.
    • C. composition of an alloy.
    • D. CO2 percentage in the flue gas.
    • Discuss


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