chemical engineering process control and instrumentation MCQs – Page 12

Practise multiple-choice questions from chemical engineering process control and instrumentation for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

chemical engineering process control and instrumentation Mcqs
221. Thermodynamic Celsius scale of temperature measurement is________________?
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A. Defined on the basis of melting point of ice and evaporation temperature of water vapor

B. Defined on the basis of melting point of ice and condensation temperature of water vapor

C. Having an interval of 100 between ice point to steam point

D. Both B. and C.
222. Response of a system to a sinusoidal input is called _____________ response?
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A. Frequency

B. Impulse

C. Unit step

D. None of these

223. Helium gas constant volume thermometer is suitable for the measurement of a temperature of ______________ C?
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A. < 0

B. > 0

C. > 800

D. < 100

224. Gain margin is equal to the_________________?
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A. Reciprocal of amplitude ratio

B. Gain in P controller

C. Amplitude ratio

D. Gain in P-I controller

225. A negative gain margin expressed in decibels means a/an ____________ system?
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A. Unstable

B. Critically damped

C. None of these

D. Stable

226. Accurate temperature measurement performance of a radiation pyrometer cannot be affected, if the ?
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A. Object has varying emissivity

B. Enhancement or attenuation of radiation occurs in the sighting path

C. Object and surrounding are at almost the same temperature

D. Object is transparent

227. For a feed back control system to be stable, the _________________?
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A. Poles of the closed loop transfer function should lie in the left half of the complex plane

B. Poles of the closed loop transfer function should lie in the right half of the complex plane

C. Roots of the characteristic equation should be real

D. Bode plots of the corresponding open loop transfer function should monotonically decrease

228. E.m.f. generated by thermocouples is of the order of ________________?
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A. Volts

B. Milli volts

C. Micro volts

D. Kilo volts

229. Temperature measuring instruments are standardised mostly with _____________ points of pure substances?
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A. Melting

B. Boiling

C. Both A. & B.

D. Neither A. nor B.

230. Which of the following is the dynamic characteristics of an instrument ?
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A. Fidelity

B. Sensitivity

C. Reproducibility

D. Dead zone

231. In Bode plot, A.R. vs. w is plotted on a/an _____________ graph paper?
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A. Ordinary

B. Semi-log

C. Triangular

D. Log-lag
232. A proportional controller with a gain of Kc is used to control a first order process. The offset will increase, if________________?
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A. Integral control action is introduced

B. Derivative control action is introduced

C. Kc is increased

D. Kc is reduced

233. Which of the following thermocouple materials does not contain nickel ?
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A. Constantan

B. None of these

C. Chromel

D. Alumel

234. Thermal conductivity measurement is used for the determination of________________?
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A. Specific gravity of petrofuels

B. O2 percentage in the flue gas

C. CO2 percentage in the flue gas

D. Composition of an alloy

235. Thermal wells are used in the temperature measurement to____________________?
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A. Increase the sensitivity

B. Increase the fidelity

C. Reduce measuring lag

D. Guard against corrosive and oxidising action on thermocouple materials
236. Nickel percentage in invar which is an iron-nickel alloy, and is used as a thermocouple material is __________________?
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A. 68

B. 36

C. 12

D. 54

237. A mercury thermometer cannot be used to measure the temperature below the freezing point of mercury, which is _____________ C?
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A. -80.9

B. -11.9

C. -60.9

D. -38.9
238. In a shell and tube heat exchanger, the inlet temperature of heating/cooling fluid is the ____________ variable?
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A. Manipulated

B. Controlled

C. None of these

D. Load
239. The ____________ of the fluid contained in the temperature sensing element (i.e., bulb) of filled system thermometers changes with change in temperature ?
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A. Volume

B. Pressure

C. Viscosity

D. All A., B. and C.
240. The operation of a Rotameter is based on ________________?
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A. Variable flow area

B. Rotation of a turbine

C. Pressure drop across a nozzle

D. Pressure at a stagnation point