Process Control Flashcards
Which of the following is an undesirable dynamic characteristic of an instrument?
A. Reproducibility
B. Dead zone
C. Time lag
D. Static error
C. Time lag
Pick out the one which is a first order instrument.
A.Mercury in glass thermometer (without any
covering or air gap)
B. Bare metallic thermometer
C. Bare vapor pressure thermometer
D. All of the above
D. All of the above
Load cells are used for the measurement of
A. stress
B. weight
C. strain
D. velocity
B. weight
Which of the following is the dynamic characteristics
of an instrument?
A. Reproducibility
B. Sensitivity
C. Dead zone
D. Fidelity
D. Fidelity
The ____ of a vapor pressure thermometer
is a functioning element.
A. pointer
B. bourdon tube
C. bulb
D. none of these
A. pointer
A negative gain margin expressed in decibels
means a/an system.
A. stable
B. unstable
C. critically damped
D. none of these
B. unstable
Thermistor has a high temperature coefficient of
resistivity which is used as the sensing element in
resistance thermometer. It is a/an
A. insulator
B. conductor
C. solid semiconductor
D. liquid semiconductor
C. solid semiconductor
Flapper nozzle is used in a/an
controller.
A. electronic
B. hydraulic
C. pneumatic
D. none of these
C. pneumatic
Working principle of radiation pyrometer is based on
the
A. Wien’s law
B. Kirchoff’s law
C. Stefan-Boltzman law
D. Seebeck effect
C. Stefan-Boltzman law
Which of the following relates the emf. generated in
a single homogeneous wire to the temperature
difference?
A. Peltier effect
B. Thomson effect
C. Seebeck effect
D. none of these
B. Thomson effect
Dilute wine was initially used as a thermometric liquid to
develop a temperature scale. The first empirical temperature scale developed
was the ____ scale.
A. Kelvin
B. Centigrade
C. Fahrenheit
D. Reaumer
C. Fahrenheit
Which of the following is a desirable characteristic
of an instrument?
A. High drift
B. High fidelity
C. High measuring lag
D. Poor reproducibility
B. High fidelity
The operation of a rotameter is based on
A. variable flow area.
B. rotation of a turbine.
C. pressure drop across a nozzle.
D. pressure at a stagnation point
A. variable flow area.
The temperature of tempering oil baths maintained at 400°C during heat treatment of steel is measured
by a/an _____ thermocouple.
A. chromel-alumel
B. iron-constantan
C. platinum-platinum/rhodium
D. none of these
B. iron-constantan
Instrumentation in a plant offers the advantage of
A. greater safety of operation
B. better quality of product
C. greater operation economy
D. all of these
D. all of these
Which of the following temperature measuring
instruments need not touch the object whose
temperature is being measured?
A. Radiation/infrared pyrometer
B. Filled system thermometer
C. Mercury in glass thermometer
D. Thermo-electric pyromete
A. Radiation/infrared pyrometer
Thermal conductivity measurement comprises the
working principle of a
A. CO2 analyzer
B. polarimeter
C. spectrometer
D. chromatograph
A. CO2 analyzer
Response of a system to a sinusoidal input is called_____ response.
A. impulse
B. unit step
C. frequency
D. none of these
frequency
The closed loop pole of a stable second order
system could be
A. both real and positive.
B. complex conjugate with positive real parts.
C. both real and negative.
D. one real positive and the other real negative
C. both real and negative.
Smoke density of the flue gas going out of the
chimney is measured by a
A. polarograph
B. thermal conductivity meter
C. photo electric cell
D. chromatograph
C. photo electric celL
Temperature measuring instruments are standardized mostly with _____ points of pure substances.
A. melting
B. boiling
C. both (A) & (B)
D. neither (A) nor (B
C. both (A) & (B)
Pick out the first order system from among the
following.
A. Damped vibrator.
B. Mercury in glass thermometer kept in boiling water.
C. Interacting system of two tanks in series.
D. Non-interacting system of two tanks in series.
B. Mercury in glass thermometer kept in boiling water.
The maximum service temperature for fibre glass
used as thermocouple wire insulation material is_____°C
A. 250
B. 500
C. 750
D. 1000
B. 500
Which of the following controllers has the least
maximum deviation?
A. P-controller
B. P-I controller
C. P-I-D controller
D. P-D controller
D. P-D controller
Volumetric expansion is the working principle of the ______
thermometers.
A. mercury in glass
B. constant volume gas
C. vapor pressure
D. bimetallic
A. mercury in glass
Which of the following measurements can be made
by the measurement of emf?
A. pH value
B. Degree of hydrolysis
C. Composition of complex ions
D. All of the above
D. All of the above
A magnetic flowmeter is
A. based on the principle of Faraday’s law.
B.capable of measuring the flow rate of slurries and
electrolytes.
C.based on the linear relationship between the fluid
flow rate and the induced voltage.
D. All of the above
D. All of the above
A magnetic flowmeter is
A. based on the principle of Faraday’s law.
B.capable of measuring the flow rate of slurries and
electrolytes.
C.based on the linear relationship between the fluid
flow rate and the induced voltage.
D. All of the above.
D. All of the above.
Zirconia probe is used for the continuous
measurement of _________flue gases going out
of the furnace.
A. oxygen in
B. carbon dioxide in
C. carbon monoxide in
D. temperature o
A. oxygen in
Strain gage pressure transducers are used to
measure pressures.
A. gage as well as vacuum
B. absolute as well as differential
C. both (A) and (B)
D. neither (A) nor (B)
C. both (A) and (B)
Compositional analysis of____ is done
using mass spectrometer.
A. an isotope
B. natural gas
C. a solid
D. an alloy
A. an isotope
The function of a transducer is to
A. modify the input signal.
B. amplify the input signal.
C.convert the primary signal into a more useful quantity, usually an electric impulse.
D. codify/decodify the input signal.
C.convert the primary signal into a more useful quantity, usually an electric impulse.
Which of the following thermocouples will give the
highest output for the same value of hot and cold
junction temperature?
A. Platinum-platinum + rhodium.
B. Iron-constantan.
C. Chromel-constantan.
D. All will give the same outpu
C. Chromel-constantan.
____ is undesirable in thermocouples used
in industries.
A. Linear relation of emf to temperature
B. Corrosion resistance
C. Oxidation resistance
D. Non-linear relation of emf to temperature
D. Non-linear relation of emf to temperature
Select the correct statement from the following.
A. The frequency response of a pure capacity process is unbounded.
B. The phase lag of a pure time delay system decreases with increasing
frequency.
C. The amplitude ratio of a pure capacity process is inversely proportional
to frequency.
D.The amplitude ratio of a pure time delay system increases with
frequency
The amplitude ratio of a pure capacity process is inversely
proportional to frequency
Continuous shell temperature measurement in a
liquid-liquid heat exchanger is done by a
A. thermocouple
B. resistance thermometer
C. mercury in glass thermometer
D. vapor pressure thermometer
thermocouple
The of a vapor pressure thermometer
is a secondary element.
A. pointer
B. Bourdon tube
C. bulb
D. none of these
B. Bourdon tube
Emf developed by a thermocouple while measuring
a temperature of 600°C is about 5.5 mV. The type of
thermocouple used is
A. chromel-alumel
B. iron-constantan
C. platinum-platinum+rhodium
D. either (A), (B) or (C)
C. platinum-platinum+rhodium
Which of the following relates the absorption &
evolution of heat at the junctions of a thermocouple
to the current flow in the circuit?
A. Seebeck effect
B. Peltier effect
C. Joule heating effect
D. Thomson effect
B. Peltier effect
In a shell and tube heat exchanger, the flow rate of
heating/cooling fluid is the _____ variable.
A. load
B. controlled
C. manipulated
D. none of these
C. manipulated
Typical specifications for design stipulates the gain
margin and phase margin to be respectively
A. >1.7 and >30°
B. <1.7 and >30°
C. <1.7 and <30°
D. >1.7 and <30°
A. >1.7 and >30°
