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Home Chemical Engineering Process Control and Instrumentation Comments

  • Question
  • Thermistors are made of


  • Options
  • A. ultra pure metals
  • B. metal oxides
  • C. iron-copper alloys
  • D. nickel-chromium alloys

  • Correct Answer
  • metal oxides 


  • Process Control and Instrumentation problems


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    • 1. Gas chromatography is used for the measurement of

    • Options
    • A. temperature
    • B. pressure
    • C. concentration
    • D. flow rate
    • Discuss
    • 2. Which of the following thermocouples can measure the maximum temperature?

    • Options
    • A. Platinum-rhodium
    • B. Tungsten-molybdenum
    • C. Chromel-alumel
    • D. Iron-constantan
    • Discuss
    • 3. Which thermocouple can be used to measure a temperature of around 1400°C?

    • Options
    • A. Copper-constantan
    • B. Aluminium-chromel
    • C. Platinum-platinum+rhodium
    • D. None of these
    • Discuss
    • 4. Dead zone is the

    • Options
    • A. same as time constant.
    • B. same as transportation lag.
    • C. maximum change in the variable that does not change the reading of the instrument.
    • D. none of these.
    • Discuss
    • 5. Flow rate of a river is measured by a/an

    • Options
    • A. pitot tube
    • B. vane meter
    • C. kennison nozzle
    • D. open weir
    • Discuss
    • 6. In a closed loop system, the process to be controlled is an integrating process with transfer function l/2s. The controller proposed to be used in an integral controller with transfer function 1/T1s. When a step change in set point is applied to such a closed loop system, the controlled variable will exhibit

    • Options
    • A. overdamped response.
    • B. underdamped response.
    • C. undamped response.
    • D. unstable response.
    • Discuss
    • 7. Bode diagram is a plot of

    • Options
    • A. log (AR) vs. log (f) and (?) vs. log (f).
    • B. log (AR) vs. f and log ? vs.f.
    • C. AR vs. log (f) and ? vs. log (f).
    • D. none of these.
    • Discuss
    • 8. The time constant of a first order process with resistance R and capacitance C is

    • Options
    • A. R + C
    • B. R - C
    • C. RC
    • D. 1/RC
    • Discuss
    • 9. A non-linear chemical system is exemplified by a/an

    • Options
    • A. isothermal CSTR
    • B. mixer
    • C. non-isothermal CSTR
    • D. none of these
    • Discuss
    • 10. Accurate temperature measurement performance of a radiation pyrometer can not be affected, if the

    • Options
    • A. enhancement or attentuation of redia-tion occurs in the sighting path.
    • B. object and surrounding are at almost the same temperature.
    • C. object has varying emissivity.
    • D. object is transparent.
    • Discuss


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