chemical engineering process control and instrumentation MCQs – Page 9

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 Review each marked answer and report any item that may be outdated or unclear.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
161. The second order system with the transfer function 4/(s2 + 2s + 4) has a damping ratio of ___________________?
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A. 2

B. 4

C. 1

D. 0.5
162. Instrumentation in a plant offers the advantage of_______________?
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A. Greater operation economy

B. Greater safety of operation

C. All A., B. and C.

D. Better quality of product

163. Emf developed by a thermocouple while measuring a temperature of 800C is about 31 mV. The type of thermocouple used is________________?
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A. Iron-constantan

B. None of these

C. Platinum-platinum + rhodium

D. Chromel-alumel
164. ____________ is the static characteristics of an instrument?
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A. Response

B. Drift

C. Tine lag

D. Dynamic error

165. Strain gage pressure transducers are used to measure _____________ pressures?
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A. Gage as well as vacuum

B. Absolute as well as differential

C. Both A. and B.

D. Neither A. nor B.

166. Strain gage uses an electrical conductor wire, which when elastically stretched increases in length and reduces in diameter. Both these dimensional changes result in ____________ in the electrical resistance of the wire ?
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A. Increase

B. Decrease

C. No change

D. Exponential decrease

167. Out of the following temperature measuring instruments, the measurement accuracy will be minimum for the ________________?
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A. Mercury in glass thermometer

B. Iron-constantan thermocouple

C. Optical pyrometer

D. Alcohol filled thermometer

168. Emf generated in a thermocouple depends on the temperature ___________________?
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A. Difference between cold junction and atmospheric temperature

B. Of hot junction only

C. Of cold junction only

D. Difference between hot and cold junctions
169. Platinum resistance thermometer is the international standard for temperature measurement between __________________?
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A. Triple point of hydrogen and freezing point of antimony

B. 13.81K to 903.9K

C. Both A. and B.

D. Neither A. nor B.

170. Which of the following instruments is not used for measuring sub-zero (<0) temperatures ?
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A. Mercury in glass thermometer

B. Platinum resistance thermometer

C. Radiation pyrometer

D. Vapor pressure thermometer

171. A magnetic flowmeter is_________________?
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A. Capable of measuring the flow rate of slurries and electrolytes

B. Based on the principle of Faradays law

C. All A., B. and C.

D. Based on the linear relationship between the fluid flow rate and the induced voltage

172. Which of the following controllers has maximum offset ?
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A. P-I controller

B. P-D controller

C. P-controller

D. P-I-D controller

173. Which of the following temperature measuring instruments need not touch the object whose temperature is being measured ?
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A. Radiation/infrared pyrometer

B. Mercury in glass thermometer

C. Filled system thermometer

D. Thermo electric pyrometer

174. The _____________ of a vapor pressure thermometer is a functioning element?
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A. Bulb

B. Pointer

C. None of these

D. Bourdon tube

175. Suppose that the gain, time constant and dead time of a process with the following transfer function: Gc(s) = 10 exp( 0.1s)/(0.5s + 1) are known with a possible error of 20% of their values. The largest permissible gain Kc of a proportional controller needs to be calculated below taking the values of process gain, time constant and dead time as________________?
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A. 12, 0.6, 0.12

B. 12, 0.4, 0.08

C. 8, 0.6, 0.08

D. 8, 0.6, 0.12

176. Feed forward controller accounts for the ______________ changes?
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A. Set point

B. Load

C. Both A. & B.

D. Neither A. nor B.

177. Thermistors are used in ____________ devices?
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A. Voltage measuring

B. Temperature measuring

C. Temperature compensating

D. Both B. & C.
178. Which of the following thermocouples is the most suitable for measuring a temperature of about 1600C in an oxidizing atmosphere ?
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A. Chromel-alumel

B. Copper-constantan

C. Iron-constantan

D. Platinum-platinum + rhodium
179. Thermal conductivity based continuous flue gas analyser makes use of varying thermal conductivity of the constituents of flue gases. Which of the following constituents of flue gases has the maximum thermal conductivity ?
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A. O2

B. N2

C. CO2

D. CO

180. Temperature measurement by optical pyrometer is done above ____________ point, which is 1063C ?
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A. Nickel

B. Antimony

C. Silver

D. Gold