Chemical Engineering MCQs – Competitive Process Control And Instrumentation MCQs
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Latest Chemical Engineering MCQs
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Latest Process Control And Instrumentation Mcqs
The most occurred mcqs of Process Control And Instrumentation in past papers. Past papers of Mcqs. Past papers of Process Control And Instrumentation Mcqs . Mcqs are the necessary part of any competitive / job related exams. The Mcqs having specific numbers in any written test. It is therefore everyone have to learn / remember the related Process Control And Instrumentation Mcqs. The Important series of Process Control And Instrumentation Mcqs are given below:
An ideal PID controller has the transfer function [1 + (1/0.55) + 0.25]. The frequency at which the magnitude ratio of the controller is 1, is________________?
A. 0.2/0.5
B. 0.5/0.2
C. 0.2 × 0.5
D. 1/√(0.2 × 0.5)
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?
A. 50
B. 10
C. 100
D. 1
Sub-zero temperature (< 0°C) can be measured by a constant volume gas thermometer employing ?
A. Helium
B. Hydrogen
C. Nitrogen
D. None of these
Which of the following measurements can be made by the measurement of emf ?
A. Degree of hydrolysis
B. pH value
C. Composition of complex ions
D. All A., B. & C.
Which thermocouple can be used to measure a temperature of around 1400°C ?
A. Aluminium-Chromel
B. Copper-constantan
C. Platinum-platinum + rhodium
D. None of these
The closed loop pole of a stable second order system could be_______________?
A. Both real and positive
B. Both real and negative
C. Complex conjugate with positive real parts
D. One real positive and the other real negative
In a single tank system, the transfer function of level to inlet flow rate is__________________?
A. 1/TS
B. R/(TS + 1)
C. R/TS
D. None of these
Humidity of air can be determined by a__________________?
A. Mass spectrometer
B. Sling psychrometer
C. Chromatograph
D. Polarimeter
A negative gain margin expressed in decibels means a/an ____________ system?
A. Critically damped
B. Unstable
C. Stable
D. None of these
The term analogous to voltage in a single tank system is the_______________?
A. Flow rate
B. Liquid volume in the tank
C. Heat content of the system
D. Level of liquid
Dome temperature of blast furnace stove is most accurately measured by a____________________?
A. Iron-constantan thermocouple
B. platinum-platinum/rhodium thermocouple
C. Radiation pyrometer
D. Platinum resistance thermometer
The pressure sensing element of elastic type pressure gauge is never made in the form of a_________________?
A. Diaphragm
B. Bellow
C. Strip
D. Bourdon tube
Minute depression of freezing point of a liquid solvent on addition of a solid solute can be best measured by a________________?
A. Beckman thermometer
B. Mercury thermometer
C. Dilatometer
D. Bimetallic thermometer
Bourdon tube is never made of________________?
A. Monel metal
B. Phosphor bronze
C. Stainless steel
D. Cast iron
For measuring the temperature of a red hot furnace, which is the most suitable instrument ?
A. Thermocouple
B. Platinum resistance thermometer
C. Optical pyrometer
D. Bimetallic thermometer
With increase in temperature, the electrical conductivity of the platinum used in the resistance thermometer ?
A. Remain constant
B. Decreases
C. Increases
D. Increases exponentially
Thermal well made of _____________ gives the fastest speed of response, while measuring temperature by thermocouples?
A. Nichrome
B. Vycor (a glass)
C. Steel
D. Inconel
Temperature control of an exothermic chemical reaction taking place in a CSTR is done with the help of cooling water flowing in a jacket around the reactor. The types of valve and controller action to be recommended are________________?
A. Air to close valve with the controller indirect acting
B. Air to open valve with the controller direct acting
C. Air to open valve with the controller indirect acting
D. Air to close valve with the controller direct acting
In Bode plot, A.R. vs. w is plotted on a/an _____________ graph paper?
A. Log-lag
B. Ordinary
C. Triangular
D. Semi-log
Thermodynamics Mcqs
The level of a liquid under pressure can be determined using___________________?
A. Diaphragm box system
B. Differential pressure manometer
C. Bubbler system
D. Air-trap system
Which of the following can measure temperatures in the range of – 20 to 300°C ?
A. Vapor pressure thermometer
B. Mercury in glass thermometer
C. Resistance thermometer
D. None of these
_____________ is an example of distributed parameter system ?
A. Tubular reactor
B. On-off controller
C. CSTR
D. None of these
The thermal emf-temperature relationship of most thermocouples is_________________?
A. Exponential
B. Parabolic
C. Linear
D. Square root
Which of the following thermocouples has the widest temperature measurement range ?
A. Chromel-alumel
B. Iron-constantan
C. Copper-constantan
D. Platinum-platinum/rhodium
In Bode plot, φ vs. ω is plotted on a/an ______________ graph paper?
A. log-log
B. Semi-log
C. Ordinary
D. Triangular
Cascade control means _______________?
A. On-off control
B. More than one feed-back loop
C. Feed forward control
D. One feed-back loop
What is the normal percentage of rhodium in platinum + rhodium element used in the thermocouple ?
A. 3
B. 0.1
C. 13
D. 29
Pick out the most suitable instrument for measuring temperature in the range of-40 to 425°C ?
A. Radiation pyrometer
B. Bimetallic thermometer
C. Mercury thermometer
D. None of these
A first order system with a time constant of 1 min is subjected to frequency response analysis. At an input frequency of 1 radian/min, the phase shift is______________?
A. -90°
B. 45°
C. -180°
D. -45°
Liquid flow rate in a small channel is best measured by a/an____________________?
A. Vane meter
B. Pitot tube
C. Weir
D. Venturimeter
Thermal wells are used in the temperature measurement to____________________?
A. Guard against corrosive and oxidising action on thermocouple materials
B. Increase the fidelity
C. Reduce measuring lag
D. Increase the sensitivity
Feed forward controller accounts for the ______________ changes?
A. Set point
B. Load
C. Both of the above
D. Neither of the above
The open loop transfer function of a process is K [{(s + 1) (s + 4)}/{(s + 2) (s + 3)}]. In the root locus diagram, the poles will be at ___________________?
A. 1, 4
B. -1, -4
C. -2, -3
D. 2, 3
Accurate temperature measurement performance of a radiation pyrometer cannot be affected, if the ?
A. Enhancement or attenuation of radiation occurs in the sighting path
B. Object and surrounding are at almost the same temperature
C. Object is transparent
D. Object has varying emissivity
Stability of a control system containing a transportation lag can be best analysed by_______________?
A. Root locus methods
B. Routh test
C. Frequency response methods
D. None of these
Thermocouple in a thermal well behaves as a true ________________?
A. Second order system (overdamped)
B. First order system
C. Multiple first order system
D. Second order system (underdamped)
Number of poles in a system with transfer function 1/(s2 + 2s2 + 1) is ________________?
A. 5
B. 2
C. 3
D. 1
Radiation pyrometers as compared to thermocouples____________________?
A. Is more affected by corrosive atmosphere
B. Can measure higher temperature
C. Can’t measure the temperature of moving objects
D. Has a slower speed of response
Bourdon gauges are used for measuring pressure (kg/cm2) ?
A. 10 (absolute)
B. > 2 (gauge)
C. < atmospheric
Thermodynamic Celsius scale of temperature measurement is________________?
A. Defined on the basis of melting point of ice and evaporation temperature of water vapor
B. Having an interval of 100° between ice point to steam point
C. Defined on the basis of melting point of ice and condensation temperature of water vapor
D. Both B. and C.
Routh test_________________?
A. Criterion provides information about the actual location of roots
B. Cannot be used to test the stability of a control system containing transportation lag
C. Cannot determine as to how many roots of the characteristics equation have positive real roots
D. Criterion is not applicable to systems with polynomial characteristic equation
A stable system is the one___________________?
A. For which the output response is bounded for all bounded input
B. Which satisfies the conditions for a servo problem
C. Which exhibits an unbounded response to a bounded input
D. None of these
Refractory Technology Mcqs
Mercury thermometer is commonly used for low temperature measurement. The freezing point and boiling point of mercury are respectively _____________ °C?
A. – 39 and 350
B. – 79 and 395
C. – 51 and 439
D. – 10 and 425
Compositional analysis of flue gas coming out of a furnace in respect of O2 and CO2% can be continuously done by a/an___________________?
A. Zirconia probe
B. Thermal conductivity cell
C. Orsat apparatus
D. Chromatograph
A manometer measures the _____________ pressure?
A. Absolute
B. Atmospheric
C. Gauge
D. None of these
Bimetal strips are not used in________________?
A. Thermostats
B. Thermocouples
C. Bimetallic thermometers
D. Relays for opening & closing of electrical circuits
In second order underdamped system ?
A. Overshoot increases for increasing damping co-efficient
B. Decay ratio = (overshoot)2
C. Decay ratio = overshoot
D. Large damping co-efficient means smaller damping
Non-metallic diaphragm used as pressure sensor in instruments is generally made of__________________?
A. Bakelite
B. Synthetic rubber
C. Teflon
D. Thick paper
Reference points i.e., ice point and steam point in Reaumer temperature scale are respectively_________________?
A. 32° & 460°
B. 0° & 80°
C. – 273° & 80°
D. 32° & 80°
Which of the following thermocouples is capable of measuring a temperature of -50°C ?
A. Platinum-platinum + rhodium
B. Iron-constantan
C. Chromel-Alumel
D. Copper-constantan
For two non-interacting first order systems connected in series, the overall transfer function is the ______________ of the individual transfer functions?
A. Product
B. Sum
C. Ratio
D. Difference
If response of a control system is to be free of offset and oscillation, the most suitable controller is_________________?
A. Proportional-derivative (PD) controller
B. Proportional controller
C. Proportional-integral (PI) controller
D. Proportional integral-derivative (PID) controller
Which of the following is not classified as a thermo electric pyrometer ?
A. Thermocouple
B. Resistance thermometer
C. Optical pyrometer (disappearing filament type)
D. Radiation pyrometer
Continuous measurement of specific gravity of a liquid is done by __________________?
A. Displacement meter
B. Contact-type electric indicators
C. Hydrometer
D. Both A. and C.
In a shell and tube heat exchanger, the outlet temperature of heating/cooling fluid is the _____________ variable?
A. Manipulated
B. Load
C. Controlled
D. None of these
Flame photometry is used for the determination of compositional analysis of_______________?
A. Natural gas
B. Alkali metals
C. Solids
D. Isotopes
Photoelectric pyrometers are suitable in the temperature range of ________________ °C?
A. 800-2500
B. 800-1600
C. 400-1600
D. 400-1000
Composition of natural gas is determined by the_________________?
A. Haldane apparatus
B. Chromatograph
C. Mass spectrometer
D. Both B. and C.
Which of the following shows maximum dip effect (indicating reverse direction of temperature change) ?
A. Mercury thermometer
B. Bimetallic thermometer
C. Radiation pyrometer
D. Thermocouple
Gain margin is equal to the_________________?
A. Gain in P controller
B. Reciprocal of amplitude ratio
C. Amplitude ratio
D. Gain in P-I controller
Thermistors which have a very high temperature co-efficient of resistivity belong to the class of solid called________________?
A. Insulators
B. Dielectrics
C. Semi conductors
D. Conductors
What is the Laplace transform of sin t ?
A. 1/(s2 + 1)
B. 1/(s2 – 1)
C. s/(1 + s2)
D. s/(s2 – 1)
Silver point temperature is ______________ °C?
A. 860.5
B. 760.5
C. 960.5
D. 1060.5
A first order system with unity gain and time constant η is subjected to a sinusoidal input of frequency w = 1/η. The amplitude ratio for this system is______________?
A. 0.5
B. 1
C. 1/√2
D. 0.25
Water is flowing through a series of four tanks and getting heated as shown in figure. It is desired to design a cascade control scheme for controlling the temperature of water leaving the tank 4 as there is a disturbance in the temperature of a second stream entering the tank 2. Select the best place to take the secondary measurement for the second loop?
A. Tank 2
B. Tank 1
C. Tank 3
D. Tank 4
Which of the following is not suitable for measuring the temperature of a red hot object in the range of 800 – 1600°C ?
A. Radiation pyrometer
B. Optical pyrometer
C. Photoelectric pyrometer
D. Thermocouples
Pyrometry refers to the measurement of temperature_________________?
A. Directly
B. With the mercurial thermometer upto 350°C
C. Which is of higher magnitude
D. All A., B. & C.
Ordinary mercury in glass thermometer is used for measuring temperature upto 120°C. However, for measuring higher temperature upto __________ °C, thermometer is made by filling nitrogen under pressure above the mercury, which stops the evaporation of mercury and reduces the chance of broken thread of mercury?
A. 350
B. 250
C. 550
D. 700
According to Bode stability criterion, a system is unstable, if the open loop frequency response exhibits an amplitude ratio exceeding unity at frequency for which phase lag is_________________?
A. 45°
B. 0°
C. 90°
D. 180°
Mcleod gauge measures the _____________ pressure?
A. Very high
B. Sub-atmospheric
C. Positive
D. Atmospheric
Continuous measurement of moisture content of paper in paper industry is done by measuring the_________________?
A. Magnetic susceptibility
B. Electrical resistance through the paper
C. Thermal conductivity through the paper
D. None of these
Liquid column manometers are used for measuring the pressure ______________ kgf/cm2?
A. < 10 (gage)
B. < 3 (gage)
C. > 2 (gage)
D. < atmospheric
Process Control And Instrumentation Mcqs
Which is the strongest paramagnetic gas ?
A. NO
B. O2
C. CO2
D. NO2
Maximum differential pressure in liquid manometer is ______________ psi?
A. 40
B. 30
C. 20
D. 50
Which of the following instruments is not used for measuring sub-zero (<0°) temperatures ?
A. Mercury in glass thermometer
B. Platinum resistance thermometer
C. Vapor pressure thermometer
D. Radiation pyrometer
Which of the following cannot measure a temperature of 1600°C ?
A. Platinum resistance thermometer
B. Photo-electric pyrometer
C. Thermocouple
D. Radiation pyrometer
In a second order under damped system, the_________________?
A. Decay ratio (which is the ratio of the sizes of successive peaks) is equal to the reciprocal of overshoot
B. Overshoot (which is a measure of how much the response exceeds the ultimate value) increase with the decrease of damping co-efficient
C. Time required for the response of first reach its ultimate value is called the response time
D. None of these
“A control system is unstable, if the open loop frequency response exhibits an amplitude ratio exceeding unity at the crossover frequency.” This is _______________ criterion?
A. Bode stability
B. Routh stability
C. Nyquist
D. None of these
A typical example of a physical system with under damped characteristic is a____________________?
A. CSTR with first order reaction
B. Spring loaded diaphragm valve
C. U-tube manometer
D. Thermocouple kept immersed in a liquid filled thermowell
In a closed loop system, the process to be controlled is an integrating process with transfer function 1/2s. 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__________________?
A. Undamped response
B. Underdamped response
C. Overdamped response
D. Unstable response
Working principle of mercury in glass thermometer is__________________?
A. Volumetric expansion
B. Linear expansion
C. Pressure rise with temperature
D. None of these
Which of the following filled system expansion thermometers has the lowest positive temperature measurement capability ?
A. Fused metal (Na or K) in steel thermometer
B. Alcohol in glass thermometer
C. Mercury in glass thermometer
D. Nitrogen in steel thermometer
The root locus plot of the roots of the characteristics equation of a closed loop system having the open loop transfer function K (s + 1)/[2 (2s + 1) (3s + 1)] will have a definite number of loci for variation of K from 0 to ∞. The number of loci is_______________?
A. 2
B. 1
C. 3
D. 4
Water is entering a storage tank at a temperature T0 and flow rate Q0 and leaving at a flow rate Q and temperature T. There are negligible heat losses in the tank. The area of cross-section of the tank is A0. The model that describes the dynamic variation of temperature of water in the tank with time is given as________________?
A. Q0(T0 – T) = Ac . h (dT/dt)
B. Q(T0 – T) = Ac . h (dT/dt)
C. Q0T0 – QT = Ac . h (dT/dt)
D. Q(T0 – T) = Ac . (dTH/dt)
The transfer function for a P-D controller is________________?
A. Kc(1+ηD s)
B. Kc ηD s
C. Kc(1 +1/ηD s)
D. Kc/ηD s
The time constant of a unity gain, first order plus time delay process is 5 min. If the phase lag at a frequency of 0.2 rad/min is 60°, then the dead time (in minutes) is________________?
A. 5π/12
B. π/12
C. π/6
D. π/3
Dead zone is the__________________?
A. Same as transportation lag
B. Same as time constant
C. Maximum change in the variable that does not change the reading of the instrument
D. None of these
All the thermocouples used for temperature measurement use dissimilar metal ________________?
A. Bars
B. Strips
C. Wires
D. Beads
A non-linear chemical system is exemplified by a/an_________________?
A. Mixer
B. Isothermal CSTR
C. Non-isothermal CSTR
D. None of these
Continuous flue gas analyser makes use of paramagnetic properties of some of its constituents, which move towards the strongest part of the magnetic field thus displacing diamagnetic gases. Which of the following gases is diamagnetic ?
A. CO2
B. NO
C. O2
D. NO2
Phase margin is equal to_______________?
A. 180° – phase lag
B. Phase lag + 180°
C. Phase lag – 180°
D. Phase lag + 90°
For the time domain function f(t) = t, the Laplace transform of ∫0 t f(t) dt is given by___________________?
A. 2/S3
B. 1/2 S3
C. 1/S3
D. 2/S2
Thermocouple is suitable for measuring_________________?
A. Very high temperatures only
B. Liquid temperatures only
C. Very low temperatures only
D. Both high and low temperatures
The frequency at which maximum amplitude ratio is attained is called the ______________ frequency?
A. Cross-over
B. Resonant
C. Corner
D. Natural
The time taken for a radioactive element to reduce to 50% of its original weight is _____________ years, if its half life period is 12 years?
A. 6
B. 18
C. 24
D. 36
Pick out the wrong statement?
A. Stirred tank with a water jacket exemplifies an interacting system
B. There is no transfer lag for a single first order system
C. Transfer lag is a characteristic of all higher order systems (other than first order systems)
D. Transfer lag decreases as the number of stages decreases
Pick out the wrong statement ?
A. Proportional controller is normally used for level control in industrial applications
B. CSTR can be considered as a distributed parameter system
C. Non-linear behaviour is exemplified by an on-off controller
D. Distributed parameter approach gives partial differential equation
Select the correct statement from the following?
A. The phase lag of a pure time delay system decreases with increasing frequency
B. The frequency response of a pure capacity process is unbounded
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
Pick out the first order system from among the following ?
A. Interacting system of two tanks in series
B. Mercury in glass thermometer kept in boiling water
C. Damped vibrator
D. Non-interacting system of two tanks in series
Pick out the one which is a first order instrument ?
A. Mercury in glass thermometer (without any covering or air gap)
B. Bare vapor pressure thermometer
C. Bare metallic thermometer
D. All A., B. and C.