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Process Control and Instrumentation MCQ Questions & Answers

Process Control and Instrumentation MCQs : This section focuses on the "Process Control and Instrumentation". These Multiple Choice Questions (MCQs) should be practiced to improve the Process Control and Instrumentation skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.




Question 1

A system with a double pole at the origin is unstable since the corresponding term in the time domain

A. Is a constant
B. Grows exponentially with time
C. Grows linearly with time
D. Decays linearly with time

View Answer

Question 2

Which of the following thermocouples has the widest temperature measurement range?

A. Iron-constantan
B. Chromel-alumel
C. Copper-constantan
D. Platinum-platinum/rhodium

View Answer

Question 3

Characteristic equation is the denominator of __________ loop transfer function.

A. Open
B. Closed
C. Both A & B
D. Neither A nor B

View Answer

Question 4

Routh stability method uses __________ loop transfer function.

A. Open
B. Closed
C. Either A or B
D. Neither A nor B

View Answer

Question 5

To increase the speed of response of a pressure spring liquid or gas expansion thermometer, the clearance space between the thermometer bulb and the thermal well should not be filled with

A. Air
B. A metal powder or graphite
C. Oil
D. Mercury

View Answer

Question 6

Which of the following can not measure a temperature of 1600°C ?

A. Platinum resistance thermometer
B. Thermocouple
C. Photo-electric pyrometer
D. Radiation pyrometer

View Answer

Question 7

Very low pressure is expressed in microns(μ), which is equal to __________ mm of Hg coloumn (absolute) at 0°C.

A. 0.0001
B. 0.001
C. 0.01
D. 0.1

View Answer

Question 8

Which thermocouple can be used to measure a temperature of around 1400°C ?

A. Copper-constantan
B. Aluminium-chromel
C. Platinum-platinum+rhodium
D. None of these

View Answer

Question 9

Mercury thermometer can be used to measure the temperature upto __________ °C.

A. 100
B. 250
C. 350
D. 750

View Answer

Question 10

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

View Answer

Question 11

A pyranometer is an instrument used for measuring the

A. Beam radiation
B. Global radiation
C. Bright sunshine period
D. None of these

View Answer

Question 12

Temperature of __________ can not be measured by an optical or radiation pyrometer.

A. Hot blast (air) from stoves
B. Molten slag flowing out of blast furnace
C. Combustion space in boilers
D. Rotary limestone calcination kiln

View Answer

Question 13

Thermistors are used in __________ devices.

A. Voltage measuring
B. Temperature measuring
C. Temperature compensating
D. Both B & C

View Answer

Question 14

Temperature of molten pig iron (1450°C) and molten slag (1500°C) flowing out of a blast furnace is measured by a/an

A. Chromel-alumel thermocouple
B. Optical pyrometer
C. Radiation pyrometer
D. Either B or C

View Answer

Question 15

For a feed back control system to be stable, the

A. Roots of the characteristic equation should be real
B. Poles of the closed loop transfer function should lie in the left half of the complex plane
C. Bode plots of the corresponding open loop transfer function should monotoni-cally decrease
D. Poles of the closed loop transfer function should lie in the right half of the complex plane

View Answer

Question 16

Thermistor, which has high temperature co-efficient of resistivity, is used as the sensing element in resistance thermometer. It is a/an

A. insulator
B. conductor
C. solid semi-conductor
D. liquid semi-conductor

View Answer

Question 17

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°

View Answer

Question 18

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.

View Answer

Question 19

Working principle of mercury in glass thermometer is

A. Volumetric expansion
B. Pressure rise with temperature
C. Linear expansion
D. None of these

View Answer

Question 20

Maximum differential pressure in liquid manometer is __________ psi.

A. 20
B. 30
C. 40
D. 50

View Answer

Question 21

Compositional analysis of flue gas coming out of a furnace in respect of O₂ and CO₂% can be continuously done by a/an

A. Orsat apparatus
B. Thermal conductivity cell
C. Zirconia probe
D. Chromatograph

View Answer

Question 22

Meleoid gauge measures the __________ pressure.

A. Positive
B. Sub-atmospheric
C. Very high
D. Atmospheric

View Answer

Question 23

What is the Laplace transform of impulse input having magnitude 'X' ?

A. X
B. X²
C. 1/X
D. 1

View Answer

Question 24

Magnetic flowmeters are generally not used for the velocity/flow measurement of hydrocarbons due to their

A. Low thermal conductivity
B. Low electrical conductivity
C. High viscosity index
D. Low flash point

View Answer

Question 25

Flow rate of those fluids which are insensitive to changes in their density, viscosity or flow velocity profile can be best measured by a

A. Magnetic flowmeter
B. Pitot tube
C. Flow nozzle type flowmeter
D. Turbine flowmeter

View Answer

Question 26

Composition of natural gas is determined by the

A. Haldane apparatus
B. Mass spectrometer
C. Chromatograph
D. Both B and C

View Answer

Question 27

Configuration of Bourdon spring tube is never made of __________ shape.

A. Circular
B. Semi-circular
C. Helical
D. Spiral

View Answer

Question 28

Response of a system to a sinusoidal input is called __________ response.

A. impluse
B. unit step
C. frequency
D. none of these

View Answer

Question 29

Temperature measurement by optical pyrometer is done above __________ point, which is 1063°C.

A. Antimony
B. Gold
C. Silver
D. Nickel

View Answer

Question 30

Which of the following controllers has maximum offset?

A. P-controller
B. P-I controller
C. P-D controller
D. P-I-D controller

View Answer

Question 31

Working principle of bimetallic thermometers is difference in linear co-efficient of thermal expansion of two strips of different metals welded together. Which of the following has the maximum thermal co-efficient of linear expansion?

A. Nickel
B. Brass
C. Chromel
D. Invar

View Answer

Question 32

Flow rate measurement of hostile acids and alkalis can be most suitably done by a/an

A. Venturimeter
B. Orificemeter
C. Magnetic flow meter
D. Hot wire anemometer

View Answer

Question 33

Positioning controllers are used for

A. Low loads
B. Temperature changes
C. High loads
D. Flow rate changes

View Answer

Question 34

Emf developed by a thermocouple while measuring a temperature of 400°C is 22 mV. The type of thermocouple used is

A. Chromel-alumel
B. Iron-constantan
C. Platinum-rhodium
D. Platinum-platinum+rhyodium

View Answer

Question 35

The level of a liquid under pressure can be determined using

A. Bubbler system
B. Differential pressure manometer
C. Diaphragm box system
D. Air-trap system

View Answer

Question 36

Working principle of disappearing filament type optical pyrometer is based on the

A. Wien's law
B. Seebeck effect
C. Kirchoff's law
D. Peltier effect

View Answer

Question 37

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.

View Answer

Question 38

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.

View Answer

Question 39

Operating range of a temperature measuring instrument is 800 to 1600°C. It could be a/an __________ pyrometer.

A. Radiation
B. Optical
C. Photoelectric
D. None of these

View Answer

Question 40

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 output.

View Answer

Question 41

Nitrogen gas constant volume thermometer is suitable for measuring a temperature of __________ °C.

A. 0-100
B. < 0
C. > 100
D. > 50

View Answer

Question 42

__________ is an example of distributed parameter system

A. Tubular reactor
B. CSTR
C. On-off controller
D. None of these

View Answer

Question 43

Polarograph is meant for the analysis of

A. Gaseous mixture
B. Miscible liquids
C. Solids
D. Isotopes

View Answer

Question 44

Which of the following filled system expansion thermometer has the capability to measure the lowest temperature?

A. Mercury in glass thermometer
B. Mercury in steel thermometer
C. Alcohol in glass thermometer
D. Fused metal (Na or K) in steel thermometer

View Answer

Question 45

Psychrometer determines the

A. Humidity of gases
B. Moisture content of solids
C. Water of crystallisation
D. Hygroscopic nature of solids

View Answer

Question 46

Which of the following is not a differential pressure flow meter?

A. Rotameter
B. Flow nozzle
C. Orificemeter
D. Venturimeter

View Answer

Question 47

Zirconia probe is used for the measurement of

A. Humidity of air
B. % CO₂ in flue gas
C. % O₂ in flue gas
D. Speed of a submarine

View Answer

Question 48

The open loop transfer function of a control system is KR/(1 + TS) . This represents

A. A first order system
B. Dead time system
C. A first order time lag
D. A second order system

View Answer

Question 49

Response of a linear control system for a change in set point is called

A. Frequency response
B. Transient response
C. Servo problem
D. Regulator problem

View Answer

Question 50

__________ 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

View Answer

Question 51

Measurement of pressure in ammonia reactor is done by

A. Bourdon gauge
B. U-tube manometer
C. Inclined tube manometer
D. Pirani guage

View Answer

Question 52

Composition of alloys can be determined by

A. Polarograph
B. Chromatograph
C. Refractrometer
D. None of these

View Answer

Question 53

Optical activity of a solution can be determined using a

A. Polarimeter
B. Polarograph
C. Dilatometer
D. Refractrometer

View Answer

Question 54

The initial value (t=0) of the unit step response of the transfer function [(s + 1)/(2s + 1)] is

A. 0
B. 1-2
C. 1
D. 2

View Answer

Question 55

Temperature measurement range of iron-constantan thermocouple is 0 to 870°C. It can be used to measure sub zero temperature, because at lower temperature

A. Emf produced is very low of the order of microvolt
B. Embrittlement of iron occurs
C. Rusting of iron takes place
D. Both B and C

View Answer

Question 56

In a single tank system, the transfer function of __________ to inlet flow rate is 1/TS+1.

A. Outlet flow rate
B. Level
C. Both A & B
D. Neither A nor B

View Answer

Question 57

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. Distributed parameter approach gives partial differential equation
D. Non-linear behaviour is exemplified by an on-off controller

View Answer

Question 58

Stabilising time for the controllers is the time required for the response to reach __________ percent of its ultimate value.

A. 63.2
B. 87.5
C. 95
D. 100

View Answer

Question 59

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

View Answer

Question 60

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/6
C. π/12
D. π/3

View Answer

Question 61

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

A. 8, 0.6, 0.08
B. 12, 0.6, 0.12
C. 8, 0.6, 0.12
D. 12, 0.4, 0.08

View Answer

Question 62

The amplitude ratio for the sinusoidal response of __________ is < 1.

A. Transportation lag
B. First order system
C. Second order system
D. None of these

View Answer

Question 63

A bolometer is

A. Used for the measurement of thermal radiation
B. An element which senses optical input and delivers thermal output
C. Both A & B
D. Neither A nor B

View Answer

Question 64

According to Bode stability criterian, a system is unstable, if the open loop frequency response exhibits an amplitude ratio exceeding unity at frequency for which phase lag is

A. 0°
B. 45°
C. 90°
D. 180°

View Answer

Question 65

Pick out the most suitable instrument for measuring temperature in the range of-40 to 425°C.

A. Mercury thermometer
B. Bimetallic thermometer
C. Radiation pyrometer
D. None of these

View Answer

Question 66

Mcleoid gauge is used to measure the

A. Point velocity
B. Flow rate
C. Vacuum
D. Pressure

View Answer

Question 67

Which of the following can measure temperatures in the range of - 20 to 300°C ?

A. Mercury in glass thermometer
B. Vapor pressure thermometer
C. Resistance thermometer
D. None of these

View Answer

Question 68

Vapour actuated pressure spring thermometer does not require ambient temperature compensation. Ambient temperature compensation is provided in gas or liquid expansion pressure spring thermometer by

A. Making the volume of thermometer bulb as large as conveniently possible
B. Reducing the volume of the capillary to a minimum
C. Reducing the volume of the receiving element to a minimum
D. All of the above

View Answer

Question 69

Phase lag of the frequency response of a second order system to a sinusoidal forcing function

A. Is 30°
B. Is 90° at the most
C. Approaches 180° asymptotically
D. Is 120°

View Answer

Question 70

For measuring the temperature of a red hot furnace, which is the most suitable instrument?

A. Platinum resistance thermometer
B. Thermocouple
C. Optical pyrometer
D. Bimetallic thermometer

View Answer

Question 71

Pressure of 0.0001 absolute psi can be measured by __________ gauge.

A. Mcloid
B. Pirani
C. Thermocouple
D. None of these

View Answer

Question 72

A negative gain margin expressed in decibels means a/an __________ system.

A. stable
B. unstable
C. critically damped
D. none of these

View Answer

Question 73

Which of the following thermometers is not suitable for distant reading upto 60 metres?

A. Vapor pressure thermometer
B. Mercury in glass thermometer
C. Constant volume gas thermometer
D. Resistance thermometer

View Answer

Question 74

In a second order under damped system, the

A. Time required for the response of first reach its ultimate value is called the response time
B. Overshoot (which is a measure of how much the response exceeds the ultimate value) increase with the decrease of damping co-efficient e
C. Decay ratio (which is the ratio of the sizes of successive peaks) is equal to the reciprocal of overshoot
D. None of these

View Answer

Question 75

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 (a), (b) & (c)

View Answer

Question 76

Thermal conductivity cell is the primary element of a/an __________ analyser.

A. Oxygen
B. Carbon dioxide
C. Carbon monoxide
D. Sulphur dioxide

View Answer

Question 77

Bode diagram is a plot of

A. Log (AR) vs. log (f) and (Φ) vs. log (f)
B. Log (AR) vs. f and log Φ vs.f
C. AR vs. log (f) and Φ vs. log (f)
D. None of these

View Answer

Question 78

Paramagnetism method is not used for the composition determination of __________ in gases.

A. Oxygen
B. Oxides of nitrogen
C. Carbon dioxide
D. Any of these

View Answer

Question 79

In Bode plot, Φ vs ω is plotted on a/an __________ graph paper.

A. Log-log
B. Ordinary
C. Semi-log
D. Triangular

View Answer

Question 80

The maximum service temperature for fibre glass used as thermocouple wire insulation material is __________ °C.

A. 250
B. 500
C. 750
D. 1000

View Answer

Question 81

A barometer measures the __________ pressure.

A. Absolute
B. Gauge
C. Absolute as well as gauge
D. Dynamic

View Answer

Question 82

A proportional controller with a gain of Kc is used to control a first order process. The offset will increase, if

A. Kc is reduced.
B. Kc is increased.
C. integral control action is introduced.
D. derivative control action is introduced.

View Answer

Question 83

Which of the following is not a composition measuring instrument?

A. Thermal conductivity cell
B. Mass spectrometer
C. Polarograph
D. Hot wire anemometer

View Answer

Question 84

Reference points i.e., ice point and steam point in Reaumer temperature scale are respectively

A. - 273° & 80°
B. 0° & 80°
C. 32° & 460°
D. 32° & 80°

View Answer

Question 85

Pirani gauge is used for the measurement of

A. Very high pressure
B. High vacuum
C. Liquid level under pressure
D. Liquid level at atmospheric pressure

View Answer

Question 86

Accurate temperature measurement performance of a radiation pyrometer can not be affected, if the

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

View Answer

Question 87

Bourdon gauges are used for measuring pressure (kg/cm² )

A. < atmospheric
B. > 2 (gauge)
C. < 2 (gauge)
D. > 10 (absolute)

View Answer

Question 88

Pressure of 0.01 psi (absolute) can be measured by __________ gauge.

A. Ionisation
B. Pirani
C. Mcloid
D. None of these

View Answer

Question 89

The second order system with the transfer function 4/(S² + 2S + 4) has a damping ratio of

A. 2
B. 0.5
C. 1
D. 4

View Answer

Question 90

A photo electric device in which the resistance of the metal is directly proportional to the light striking on it, is known as photo-conductive cell. Photoelectric transducers are used for the measurement of those parameters, which can be used to produce variation in

A. Light intensity
B. Current
C. Flux density
D. Voltage

View Answer

Question 91

Continuous measurement of moisture in paper is done by

A. Sling psychrometer
B. Hair-hygrometer
C. Weighing
D. High resistance Wheatstone's bridge circuit

View Answer

Question 92

Which of the following filled system expansion thermometers has the lowest positive temperature measurement capability?

A. Mercury in glass thermometer
B. Alcohol in glass thermometer
C. Fused metal (Na or K) in steel thermometer
D. Nitrogen in steel thermometer

View Answer

Question 93

Process degree of freedom indicates __________ number of controllers to be used.

A. The maximum
B. The minimum
C. Both maximum and the minimum
D. Nothing about the

View Answer

Question 94

Use of I-control along with P-control facilitates

A. Elimination of offset
B. Reduction of offset
C. Reduction of stability time
D. None of these

View Answer

Question 95

__________ type of element is normally not used in the bimetallic thermometers.

A. Flat spiral
B. Bourdon tube
C. Single helix
D. Multiple helix

View Answer

Question 96

When a bare thermocouple is covered by a protective sheath, the response becomes

A. Faster and oscillatory
B. Faster and non-oscillatory
C. Slower and oscillatory
D. Slower and non-oscillatory

View Answer

Question 97

__________ thermometer can not measure sub-zero (< 0° C) temperature,

A. Mercury in glass
B. Bimetallic
C. Vapor pressure
D. Resistance

View Answer

Question 98

What is the dynamic error in a critically damped second order instrument for a ramp input (AT)?

A. 0.5 AT
B. 2 AT
C. √AT
D. 1.5 AT

View Answer

Question 99

A constant volume gas thermometer employing __________ is used to measure sub-zero (i.e., < 0° C) temperature.

A. Helium
B. Hydrogen
C. Nitrogen
D. None of these

View Answer

Question 100

The __________ of a vapor pressure thermometer is a secondary element.

A. pointer
B. Bourdon tube
C. bulb
D. none ofthese

View Answer

Question 101

__________ stability method uses open loop transfer function.

A. Nyquist
B. Mikhalov
C. Ruth
D. None of these

View Answer

Question 102

The thermal emf-temperature relationship of most thermocouples is

A. Linear
B. Parabolic
C. Exponential
D. Square root

View Answer

Question 103

Emf generated in a thermocouple depends on the temperature

A. Of cold junction only
B. Of hot junction only
C. Difference between hot and cold junctions
D. Difference between cold junction and atmospheric temperature

View Answer

Question 104

Bode diagram are generated from output response of the system subjected to which of the following input?

A. Impulse
B. Step
C. Ramp
D. Sinusoidal

View Answer

Question 105

Which of the following is not classified as a thermo electric pyrometer?

A. Resistance thermometer
B. Thermocouple
C. Optical pyrometer (disappearing filament type)
D. Radiation pyrometer

View Answer

Question 106

Liquid flow rate in a small channel is best measured by a/an

A. Weir
B. Pitot tube
C. Vane meter
D. Venturimeter

View Answer

Question 107

For an input forcing function, X(t) = 2t², the Laplace transform of this function is

A. 2/s²
B. 4/s²
C. 2/s³
D. 4/s³

View Answer

Question 108

An aneroid barometer measures the __________ pressure.

A. Atmospheric
B. Absolute
C. Vacuum
D. Gage

View Answer

Question 109

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 open valve with the controller direct acting
B. Air to close valve with the controller indirect acting
C. Air to open valve with the controller indirect acting
D. Air to close valve with the controller direct acting

View Answer

Question 110

Nichol's chart deals with

A. A.R. vs. phase lag of first order.
B. A.R. vs. phase lag of second order.
C. closed loop values vs. open loop values.
D. frequency response values of controllers.

View Answer

Question 111

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. 45°
B. -90°
C. -180°
D. -45°

View Answer

Question 112

Which of the following is never used as an element of industrial resistance thermometer?

A. Lead
B. Nickel
C. Copper
D. 30% iron + 70% nickel

View Answer

Question 113

Which of the following judges the accuracy of an instrument?

A. Dead zone
B. Drift
C. Static error
D. None of these

View Answer

Question 114

The transfer function of a first order system is

A. 1/(Ts + 1)
B. 1/Ts
C. S/(Ts + 1)
D. None of these

View Answer

Question 115

Liquid levels in autocalves are measued by

A. Simple float
B. Differential float type manometer
C. Glass gauge
D. None of these

View Answer

Question 116

Non-metallic diaphragm used as pressure sensor in instruments is generally made of

A. Teflon
B. Synthetic rubber
C. Bakelite
D. Thick paper

View Answer

Question 117

Humidity of air can be determined by a

A. Chromatograph
B. Sling psychrometer
C. Mass spectrometer
D. Polarimeter

View Answer

Question 118

__________ temperature scale assigns 0° to the 'ice point' and 80° to the 'steam point'.

A. Celcius
B. Rankine
C. Reumur
D. Farenhite

View Answer

Question 119

Relationship between absorption/evolution of heat at the thermocouple junctions and the current flow in the circuit is given by __________ effect.

A. Peltier
B. Thomson
C. Seebeck
D. None of these

View Answer

Question 120

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.

View Answer

Question 121

If response of a control system is to be free of offset and oscillation, the most suitable controller is

A. Proportional controller
B. Proportional-derivative(PD)controller
C. Proportional-integral (PI) controller
D. Proportional integral-derivative (PID) controller

View Answer

Question 122

Mercury thermometer is commonly used for low temperature measruement. The freezing point and boiling point of mercury are respectively __________ °C.

A. - 39 and 350
B. - 51 and 439
C. - 79 and 395
D. - 10 and 425

View Answer

Question 123

What is the normal percentage of rhodium in platinum + rhodium element used in the thermocouple?

A. 0.1
B. 3
C. 13
D. 29

View Answer

Question 124

Volumetric expansion is the working principle of the __________ thermometers.

A. mercury in glass
B. constant volume gas
C. vapor pressure
D. bimetallic

View Answer

Question 125

A first order system with unity gain and time constant τ is subjected to a sinusoidal input of frequency w = 1/τ. The amplitude ratio for this system is

A. 1
B. 0.5
C. 1/√2
D. 0.25

View Answer

Question 126

Which of the following thermocouples is the most suitable for measuring a temperature of about 1600°C in an oxidizing atmosphere?

A. Platinum-platinum + rhodium
B. Iron-constantan
C. Copper-constantan
D. Chromel-alumel

View Answer

Question 127

Liquid discharge from a tank or reservoir can not be measured by

A. Orificemeters
B. Weirs
C. Mouthpieces
D. Notches

View Answer

Question 128

Instrumentation in a plant offers the advantage of

A. greater safety of operation
B. better quality of product
C. greater operation economy
D. all (a), (b) and (c)

View Answer

Question 129

Hot wire anemometer is used for the measurement of

A. Flow rates of fluids
B. Flow rates of granular solids
C. Very high temperature
D. Thermal conductivity of gases

View Answer

Question 130

Photoelectric pyrometers are suitable in the temperature range of __________ °C.

A. 400-1600
B. 800-1600
C. 800-2500
D. 400-1000

View Answer

Question 131

The term analogous to the electrical current in a thermal system is the

A. Temperature difference
B. Heat flow rate
C. Heat content in the system
D. None of these

View Answer

Question 132

The unit of 'time constant' of a system is the same as that of

A. Velocity
B. Time
C. (time)⁻¹
D. None of these

View Answer

Question 133

Working principle of radiation pyrometer is based on the

A. Wien's law
B. Kirchoffs law
C. Stafan-Boltzman law
D. Seebeck effect

View Answer

Question 134

Nichol's chart deals with

A. A.R. vs. phase lag of first order
B. A.R. vs. phase lag of second order
C. Closed loop values vs. open loop values
D. Frequency response values of controllers

View Answer

Question 135

Radiation pyrometers as compared to thermocouples

A. Has a slower speed of response
B. Can measure higher temperature
C. Can't measure the temperature of moving objects
D. Is more affected by corrosive atmosphere

View Answer

Question 136

Stroboscope is used for the measurement of

A. Rpm of a flywheel
B. Frequency of light
C. Depression of freezing point
D. Liquid level under pressure

View Answer

Question 137

The transfer function of a pure dead time system with dead time τd is

A. 1/(τds + 1)
B. Τds + 1
C. E-τds
D. Eτds

View Answer

Question 138

__________ controller has the maximum stabilising time.

A. P
B. PD
C. PI
D. PID

View Answer

Question 139

For two non-interacting first order systems connected in series, the overall transfer function is the __________ of the individual transfer functions.

A. Product
B. Ratio
C. Sum
D. Difference

View Answer

Question 140

Silver point temperature is __________ °C.

A. 760.5
B. 860.5
C. 960.5
D. 1060.5

View Answer

Question 141

A system with transfer function (2S/4S) + 1 is of __________ order.

A. Zero
B. 1st
C. 2nd
D. 3rd

View Answer

Question 142

0n-off control which is a special case of proportional control, has a band width of about __________ percent.

A. 100
B. 75
C. 25
D. 0

View Answer

Question 143

Pick out the wrong statement.

A. There is no transfer lag for a single first order system
B. Stirred tank with a water jacket exemplifies an interacting system
C. Transfer lag is a characteristics of all higher order systems (other than first order systems)
D. Transfer lag decreases as the number of stages decreases

View Answer

Question 144

The deflection in diaphragm (which is used as pressure sensor in pneumatic and electronic instruments) is dependent on the metal thickness, its diameter (d) and shape & number of corrugations. Its deflection is proportional to

A. D
B. D²
C. D³
D. D⁴

View Answer

Question 145

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

View Answer

Question 146

Which of the following does not figure in the list of seven substances selected for international temperature scale?

A. Ice (F.P) and steam (B.P)
B. Oxygen and sulphur (B.P)
C. Antimony and silver (F.P)
D. Zinc (B.P) and mercury (F.P)

View Answer

Question 147

Starting temperature of optical radiation pyrometer is __________ °C.

A. 800
B. 400
C. 1200
D. 1500

View Answer

Question 148

Which of the following is not a second order instrument?

A. Mercury in glass thermometer with covering
B. Bare mercury in glass thermometer
C. Pressure gauge with one bellow, two tubes and a tank
D. None of these

View Answer

Question 149

Thermal conductivity measurement com-prises the working principle of a

A. CO₂ analyser
B. Polarimeter
C. Spectrometer
D. Chromatograph

View Answer

Question 150

Presence of a small amount of water in the organic systems can be determined by the __________ method.

A. Electrical conductivity
B. Polarimetry
C. Emission spectroscopy
D. Dielectric constant end loss factor

View Answer

Question 151

Phase margin is equal to

A. 180° - phase lag
B. Phase lag - 180°
C. Phase lag + 180°
D. Phase lag + 90°

View Answer

Question 152

A manometer measures the __________ pressure.

A. Atmospheric
B. Absolute
C. Gauge
D. None of these

View Answer

Question 153

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)

View Answer

Question 154

Which of the following thermocouples has the least temperature measurement range?

A. Copper-constantan
B. Chromel-alumel
C. Platinum-platinum/rhodium
D. Iron-constantan

View Answer

Question 155

Which of the following is a desirable characteristic of an instrument?

A. High drift
B. High fidelity
C. High measuring lag
D. Poor reproducibility

View Answer

Question 156

Mass spectrometer is used for the composition analysis of

A. Alloys
B. Solids
C. Isotopes
D. None of these

View Answer

Question 157

Thermocouple in a thermal well behaves as a true

A. First order system
B. Second order system (overdamped)
C. Multiple first order system
D. Second order system (underdamped)

View Answer

Question 158

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

View Answer

Question 159

Number of poles in a system with transfer function 1/(s² + 2s² + 1) is

A. 2
B. 5
C. 3
D. 1

View Answer

Question 160

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

View Answer

Question 161

A non-linear chemical system is exemplified by a/an

A. Isothermal CSTR
B. Mixer
C. Non-isothermal CSTR
D. None of these

View Answer

Question 162

A mercury barometer measures the __________ pressure.

A. Atmospheric
B. Gauge
C. Vacuum
D. Absolute

View Answer

Question 163

Which of the following is not the triple point of water ?

A. 32°R
B. 273°K
C. 492°R
D. 32°F

View Answer

Question 164

Gas chromatography is used for the measurement of

A. Temperature
B. Pressure
C. Concentration
D. Flow rate

View Answer

Question 165

The __________ of a vapor pressure thermometer is a primary element.

A. Pointer
B. Bourdon tube
C. Bulb
D. None of these

View Answer

Question 166

Flow rate through an orifice is __________ the pressure differential.

A. Proportional to
B. Inversely proportional to the square root of
C. Proportional to the square root of
D. Inversely proportional to the square of

View Answer

Question 167

The __________ of the fluid contained in the temperature sensing element (i.e., bulb) of filled system thermometers changes with change in temperature.

A. Pressure
B. Volume
C. Viscosity
D. All of the above

View Answer

Question 168

Load cells are used for the measurement of

A. stress
B. weight
C. strain
D. velocity

View Answer

Question 169

The transfer function for a P-D controller is

A. Kc(1+τD s)
B. Kc(1 +1/τD s)
C. Kc τD s
D. Kc/τD s

View Answer

Question 170

Sub-zero temperature (< 0°C) can be measured by a constant volume gas thermometer employing

A. Helium
B. Nitrogen
C. Hydrogen
D. None of these

View Answer

Question 171

Degree to which an instrument indicates the changes in measured variable without dynamic error is called its

A. Speed of response
B. Reproducibility
C. Fidielity
D. Static characteristics

View Answer

Question 172

All the thermocouples used for temperature measurement use dissimilar metal

A. Strips
B. Bars
C. Wires
D. Beads

View Answer

Question 173

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

View Answer

Question 174

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

View Answer

Question 175

Temperature measuring instruments are standardised mostly with __________ points of pure substances.

A. Melting
B. Boiling
C. Both A & B
D. Neither A nor B

View Answer

Question 176

Thermisters which have a very high temperature co-efficient of resistivity belong to the class of solid called

A. Dielectrics
B. Insulators
C. Semi conductors
D. Conductors

View Answer

Question 177

In a shell and tube heat exchanger, the outlet temperature of heating/cooling fluid is the __________ variable.

A. Load
B. Manipulated
C. Controlled
D. None of these

View Answer

Question 178

In an exothermic chemical reactor, the manipulated variable is the flow rate of

A. Coolant
B. Reactants
C. Product
D. None of these

View Answer

Question 179

Thermal well made of __________ gives the fastest speed of response, while measuring temperature by thermocouples.

A. Steel
B. Vycor (a glass)
C. Nichrome
D. Inconel

View Answer

Question 180

Range of hydrogen gas constant volume themometer is __________ °C.

A. -10 to 20
B. 0 to 100
C. 100 - 500
D. 400 - 1000

View Answer

Question 181

Compositional analysis of __________ is done using mass spectrometer.

A. an isotope
B. natural gas
C. a solid
D. an alloy

View Answer

Question 182

Dead zone is the

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

View Answer

Question 183

Which of the following is the dynamic characteristics of an instrument ?

A. Reproducibility
B. Sensitivity
C. Dead zone
D. Fidelity

View Answer

Question 184

Out of the following temperature measuring instruments, the measurement accuracy will be minimum for the

A. Mercury in glass thermometer
B. Optical pyrometer
C. Iron-constantan thermocouple
D. Alcohol filled thermometer

View Answer

Question 185

A control system has the following transfer function F(s) = (s - 1)(s + 1)/s(s - 2)(s + 4)The initial value of the corresponding time function is

A. 1
B. 1-8
C. 7-8
D. -1

View Answer

Question 186

Which of the following is not suitable for measuring the temperature of a red hot object in the range of 800 - 1600°C?

A. Optical pyrometer
B. Radiation pyrometer
C. Photoelectric pyrometer
D. Thermocouples

View Answer

Question 187

A pyrheliometer is an instrument used for measuring the

A. Bright sunshine period
B. Beam radiation
C. Diffuse radiation
D. None of these

View Answer

Question 188

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

A. Overdamped response
B. Underdamped response
C. Undamped response
D. Unstable response

View Answer

Question 189

Feed forward controller accounts for the __________ changes.

A. Set point
B. Load
C. Both A & B
D. Neither A nor B

View Answer

Question 190

Zirconia probe is used for the continuous measurment of __________ flue gases going out of the furnace.

A. oxygen in
B. carbon dioxide in
C. carbon monoxide in
D. temperature of

View Answer

Question 191

On-off controllers are normally used for

A. Low loads
B. Temperature changes
C. Flow rate changes
D. None of these

View Answer

Question 192

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

View Answer

Question 193

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

View Answer

Question 194

The Laplace transform of exp(at), where a > 0, is defined only for the Laplace parameter, s > a since

A. The function is exponential
B. The Laplace transform of integral of exp(at) has finite values only for s > a
C. The Laplace transform integral of exp(at) has initial values only for s > a
D. The function exp(at) is piece-wise continuous only for s > a

View Answer

Question 195

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.

View Answer

Question 196

Flow rate of sludge is not measured by a/an

A. Orificemeter
B. Open weir
C. Kennison nozzle
D. Both B & C

View Answer

Question 197

What is the ratio of output amplitude to input amplitude for a sinusoidal forcing function in a first order system?

A. 1
B. >1
C. < 1
D. None of these

View Answer

Question 198

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 pyrometer

View Answer

Question 199

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. 1
B. 3
C. 4
D. 2

View Answer

Question 200

Which of the following thermocouples is incapable of measuring sub-zero (i.e., < 0°C) temperature?

A. Chromel-alumel
B. Iron-constantan
C. Platinum-platinum + rhodium
D. Copper-constantan

View Answer

Question 201

For an input forcing function, X(t) = 2t2, the Laplace transform of this function is

A. 2/s2
B. 4/s2
C. 2/s3
D. 4/s3

View Answer

Question 202

Liquid flow rate in an open channel can not be measured by a/an

A. Orifice meter
B. Cipolletti weir
C. Rectangular weir
D. V-notch

View Answer

Question 203

Liquid argon level in a pressurised storage tank (at 3 kg/cm² ) is measured by a/an

A. Gage glass
B. External float gage
C. Differential pressure gage
D. None of these

View Answer

Question 204

An emf of the order of mV is generated when two solutions of different hydrogen ion concentration are separated by a thin glass wall. This is the working principle of a

A. PH meter
B. Polarimeter
C. Chromatograph
D. Polarograph

View Answer

Question 205

Measurement of sub-zero Celcius temperature in industry is done most commonly by

A. Thermocouples
B. Resistance thermometers
C. Gas thermometers
D. Bi-metallic thermometers

View Answer

Question 206

Which of the following is the dynamic characteristics of an instrument?

A. Reproducibility
B. Sensitivity
C. Dead zone
D. Fidelity

View Answer

Question 207

The fluid used in hydraulic controller is

A. Water
B. Steam
C. Air
D. Oil

View Answer

Question 208

Liquid column manometers are used for measuring the pressure __________ kgf/cm² .

A. > 2(gage)
B. < 3 (gage)
C. < 10 (gage)
D. < atmospheric

View Answer

Question 209

Dead zone in an instrument must be less than __________ percent of the scale.

A. 0.2
B. 1.5
C. 4
D. 8

View Answer

Question 210

Which of the following is not a variable area flow meter?

A. Piston type meter
B. Rotameter
C. Magnetic flow meter
D. Orifice and tapered plug meter

View Answer

Question 211

Cascade control means

A. Feed forward control
B. More than one feed-back loop
C. On-off control
D. One feed-back loop

View Answer

Question 212

Phase lag of the sinusoidal response of a first order system is

A. 120°
B. 30°
C. 180°
D. 90°

View Answer

Question 213

Pick out the wrong statement.

A. O₂, NO and NO₂ exhibit paramagnetic properties as a result of unpaired electrons
B. CO₂ is the strongest paramagnetic gas
C. Paramagnetic susceptibility of gases decreases with temperature
D. Paramagnetic susceptibility of gases permits the measurement of their concentration

View Answer

Question 214

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

View Answer

Question 215

A bimetallic thermometer as compared to industrial mercury in glass thermometer has almost the same

A. Temperature measuring range (- 40°C to 450°C)
B. Accuracy (± 1% of span)
C. Speed of response
D. All of the above

View Answer

Question 216

Transfer function of transportation lag is

A. ETS
B. E-TS
C. 1/(TS + 1)
D. None of these

View Answer

Question 217

__________ are analysed using a polarograph.

A. Isotonic solutions
B. Solids
C. Liquids
D. Gases

View Answer

Question 218

Dome temperature of blast furnace stove is most accurately measured by a

A. Radiation pyrometer
B. Platinum-platinum/rhodium ther-mocuple
C. Iron-constantan thermocouple
D. Platinum resistance thermometer

View Answer

Question 219

Find the ultimate gain and frequency for a proportional controller in the case of a process having the transfer function Gp(s) = 1/(4s + 1)(2s + 1)(s + 1).

A. W = 1/√14, Kc = 45/7√14
B. W = √(7/6), Kc = 46/3
C. W = 1, Kc = 13
D. W = √(7/8), Kc = 45/4

View Answer

Question 220

The root locus method, a pole of a transfer function G(s) is the value of s for which G(s) approaches

A. -1
B. 0
C. 1
D. ∞

View Answer

Question 221

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 (a), (b) and (c).

View Answer

Question 222

Which is the most suitable instrument for measuring pressure below 3 microns?

A. Mcleoid gauge
B. Alphatron
C. Ionisation gauge
D. Bourdon guage

View Answer

Question 223

A typical example of a physical system with under damped characteristic is a

A. U-tube manometer
B. Spring loaded diaphragm valve
C. CSTR with first order reaction
D. Thermocouple kept immersed in a liquid filled thermowell

View Answer

Question 224

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. Dilatometer
C. Mercury thermometer
D. Bimetallic thermometer

View Answer

Question 225

The frequency response of a first order system, has a phase shift with lower and upper bounds given by

A. - ∞, π/2
B. -π/2, π/2
C. -π/2, 0
D. 0, π/2

View Answer

Question 226

Which is the strongest paramagnetic gas?

A. CO₂
B. O₂
C. NO
D. NO₂

View Answer

Question 227

In a shell and tube heat exchanger, the inlet temperature of heating/cooling fluid is the __________ variable.

A. Load
B. Manipulated
C. Controlled
D. None of these

View Answer

Question 228

Which of the following flow-metering instru-ments is an areameter?

A. Venturimeter
B. Rotameter
C. Pitot tube
D. Hot wire anemometer

View Answer

Question 229

Transfer function of transportation lag is

A. eTS
B. e-TS

View Answer

Question 230

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. 250
B. 350
C. 550
D. 700

View Answer

Question 231

Conversion formula for converting amplitude ratio (AR) into decibels is

A. Decibel = 20 log10 (AR)
B. Decibel = 20 loge (AR)
C. Decibel = 20 log10 (AR)0.5
D. Decibel = 20 loge (AR)0.5

View Answer

Question 232

Alphatron measures pressure __________ microns.

A. < 1
B. < 3
C. > 3
D. < 0.1

View Answer

Question 233

Out of the following themocouple wire insulating material, the highest temperature rating is for

A. Teflon
B. Ceramic fibre
C. Asbestos
D. Fibre glass

View Answer

Question 234

A stable system is the one

A. For which the output response is bounded for all bounded input
B. Which exhibits an unbounded response to a bounded input
C. Which satisfies the conditions for a servo problem
D. None of these

View Answer

Question 235

Emission spectroscopy is used for

A. Solids and metal analysis
B. Determining water purity
C. Determination of CO₂ in gases
D. NOxdetermination

View Answer

Question 236

Gain margin is equal to the

A. Amplitude ratio
B. Reciprocal of amplitude ratio
C. Gain in P controller
D. Gain in P-I controller

View Answer

Question 237

The inverse Laplace transform of the function f(s) = 1/S(1 + S) is

A. 1 + et
B. 1 - et
C. 1 + e-t
D. 1 - e-t

View Answer

Question 238

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

View Answer

Question 239

Which of the following is not a speed measuring instrument?

A. Psychrometer
B. Stroboscope
C. Tachometer
D. All of the above

View Answer

Question 240

In Bode plot, A.R. vs. w is plotted on a/an __________ graph paper.

A. Log-lag
B. Triangular
C. Ordinary
D. Semi-log

View Answer

Question 241

With increase in temperature, the electrical conductivity of the platinum used in the resistance thermometer

A. Increases
B. Decreases
C. Remains constant
D. Increases exponentially

View Answer

Question 242

The temperature range for which copper resistance thermometer can be used is __________ °C

A. 0 to 150
B. -200 to 150
C. 350 to 750
D. 500 to 900

View Answer

Question 243

Platinum resistance thermometer is the international standard for temperature measurement between

A. Triple point of hydrogen and freezing point of antimony
B. 13.81°K to 903.9°K
C. Both A and B
D. Neither A nor B

View Answer

Question 244

The __________ of a vapor pressure thermometer is a functioning element.

A. pointer
B. bourdon tube
C. bulb
D. none of these

View Answer

Question 245

The pressure sensing element of elastic type pressure gauge is never made in the form of a

A. Bellow
B. Diaphragm
C. Strip
D. Bourdon tube

View Answer

Question 246

Flame photometry is used for the determination of compositional analysis of

A. Solids
B. Alkali metals
C. Natural gas
D. Isotopes

View Answer

Question 247

Concentration of sugar solution can be determined by the

A. Polarimetry
B. Flame photometry
C. Emission spectroscopy
D. Oscillometry

View Answer

Question 248

Bourdon tube is never made of

A. Phosphor bronze
B. Monel metal
C. Stainless steel
D. Cast iron

View Answer

Question 249

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°

View Answer

Question 250

Temperature measuring instruments are standardised mostly with __________ points of pure substances.

A. melting
B. boiling
C. both (a) & (b)
D. neither (a) nor (b)

View Answer

Question 251

Which of the following is a desirable characteristic of an instrument ?

A. High drift
B. High fidelity
C. High measuring lag
D. Poor reproducibility

View Answer

Question 252

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?

A. CO₂
B. N₂
C. O₂
D. CO

View Answer

Question 253

Identify an unbounded input from inputs whose transfer functions are given below

A. 1
B. 1/S
C. 1/S²
D. 1/(S² + 1)

View Answer

Question 254

The frequency at which maximum amplitude ratio is attained is called the __________ frequency.

A. Corner
B. Resonant
C. Cross-over
D. Natural

View Answer

Question 255

When the damping co-efficient (ξ) is unity, the system is

A. Overdamped
B. Critically damped
C. Underdamped
D. Highly fluctuating

View Answer

Question 256

Mercury manometer (U-tube type) exemplifies a __________ order system.

A. Zero
B. First
C. Second
D. Third

View Answer

Question 257

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

View Answer

Question 258

For increased speed of response of an expansion pressure spring thermometer, the thermometer bulb should have a

A. Large area but small mass
B. High thermal conductivity
C. Small specific heat
D. All of the above

View Answer

Question 259

Pyrometry refers to the measurement of temperature

A. With the mercurial thermometer upto 350°C
B. Directly
C. Which is of higher magnitude
D. All of the above

View Answer

Question 260

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 pyrometer

View Answer

Question 261

__________ is the static characteristics of an instrument,

A. Response
B. Tine lag
C. Drift
D. Dynamic error

View Answer

Question 262

The transfer function of a process is 1/(16s² + 8s + 4). If a step change is introduced into the system, then the response will be

A. Under damped
B. Critically damped
C. Over damped
D. None of these

View Answer

Question 263

The term analogous to voltage in a single tank system is the

A. Heat content of the system
B. Liquid volume in the tank
C. Flow rate
D. Level of liquid

View Answer

Question 264

Thermal conductivity measurement is used for the determination of

A. O₂ percentage in the flue gas
B. Specific gravity of petrofuels
C. Composition of an alloy
D. CO₂ percentage in the flue gas

View Answer

Question 265

Time constant is the

A. Time taken by the controlled variable to reach 63.2% of its full change
B. Same as transportation lag
C. Same as dead time
D. Time required by the measured variable to reach 63.2% of its ultimate change

View Answer

Question 266

In second order underdamped system,

A. Decay ratio = overshoot
B. Decay ratio = (overshoot)²
C. Overshoot increases for increasing damping co-efficient
D. Large damping co-efficient means smaller damping

View Answer

Question 267

Which of the following shows maximum dip effect (indicating reverse direction of temperature change)?

A. Mercury thermometer
B. Radiation pyrometer
C. Bimetallic thermometer
D. Thermocouple

View Answer

Question 268

Emf developed by a thermocouple while measuring a temperature of 800°C is about 31 mV. The type of thermocouple used is

A. Chromel-alumel
B. Iron-constantan
C. Platinum-platinum+rhodium
D. None of these

View Answer

Question 269

High temperature of around 2000°C of incandescent gas mantles is measured by a/an

A. Specially designed thermocouple
B. Optical pyrometer
C. Radiation pyrometer
D. None of these

View Answer

Question 270

A simple pitot tube measures the

A. Average velocity
B. Maximum velocity
C. Point velocity
D. Static pressure

View Answer

Question 271

Stalagmometer is used for the measurement of

A. Kinematic viscosity
B. Surface tension
C. Refractive index
D. Optical activity

View Answer

Question 272

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 of the above

View Answer

Question 273

In a single tank system, the transfer function of level to inlet flow rate is

A. R/TS
B. R/(TS + 1)
C. l(TS + l)
D. 1/TS

View Answer

Question 274

Which of the systems having following transfer functions is stable?

A. 1/(s²+ 2)
B. 1/(s²-2s + 3)
C. 1/(s² + 2s + 2)
D. Exp(-20s)/(s² + 2s-l)

View Answer

Question 275

What is the Laplace transform of sin t ?

A. 1/(s² + 1)
B. S/(s² + 1)
C. 1/(s² - 1)
D. S/(s² - 1)

View Answer

Question 276

Thermal wells used in temperature measurements should have

A. Very thick walls
B. Low emissivity
C. Polished surface
D. High transmissivity of radiation

View Answer

Question 277

The deflection of the free end of the bimetallic strips in a bimetallic thermometer with temperature is nearly

A. Linear
B. Non-linear
C. Parabolic
D. Hyperbolic

View Answer

Question 278

Flapper nozzle is used in a/an __________ controller.

A. electronic
B. hydraulic
C. pneumatic
D. none of these

View Answer

Question 279

Continuous measurement of specific gravity of a liquid is done by

A. Hydrometer
B. Contact-type electric indicators
C. Displacement meter
D. Both A and C

View Answer

Question 280

Helium gas constant volume thermometer is suitable for the measurement of a temperature of __________ °C.

A. < 100
B. < 0
C. > 0
D. > 800

View Answer

Question 281

Flow rate of a river is measured by a/an

A. Pitot tube
B. Vane meter
C. Kennison nozzle
D. Open weir

View Answer

Question 282

Pick out the wrong statement.

A. O2, NO and NO2 exhibit paramagnetic properties as a result of unpaired electrons.
B. CO2 is the strongest paramagnetic gas.
C. Paramagnetic susceptibility of gases decreases with temperature.
D. Paramagnetic susceptibility of gases permits the measurement of their concentration.

View Answer

Question 283

Bode stability method uses __________ loop transfer function.

A. Open
B. Closed
C. Either A or B
D. Neither A nor B

View Answer

Question 284

Thermodynamic celcius scale of temperature measurement is

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

View Answer

Question 285

Specific gravity of a liquid can not be measured by a/an

A. Anemometer
B. Specific gravity bottle
C. Pycnometer
D. Hydrometer

View Answer

Question 286

Continuous measurement of moisture content of paper in paper industry is done by measuring the

A. Thermal conductivity through the paper
B. Electrical resistance through the paper
C. Magnetic susceptibility
D. None of these

View Answer

Question 287

Which of the following is not a mechanical pressure sensing element?

A. Bellows
B. Diaphragm
C. Bourdon tube
D. U-tube

View Answer

Question 288

The amplitude ratio for the sinusoidal response of a __________ is 1.

A. First order system
B. Second order system
C. Transportation lag
D. None of these

View Answer

Question 289

Dilute wine was used as a thermometric liquid initially to develop temperature scale. First emperical temperature scale developed was the __________ scale.

A. Kelvin
B. Centigrade
C. Fahrenheit
D. Reaumer

View Answer

Question 290

Thermal wells are used in the temperature measurement to

A. Guard against corrosive and oxidising action on thermocouple materials
B. Reduce measuring lag
C. Increase the fidelity
D. Increase the sensitivity

View Answer

Question 291

Thermocouple is suitable for measuring

A. Liquid temperatures only
B. Very high temperatures only
C. Very low temperatures only
D. Both high and low temperatures

View Answer

Question 292

Reset rate is the another term used for __________ time.

A. Dead
B. Integral
C. Derivative
D. None of these

View Answer

Question 293

The characteristic equation for the control system with a closed loop transfer function G₁/1 + G₂ is given by 1 + G₂ = 0. The characteristic equation for the control system

A. Depends only upon the open loop transfer function
B. Determines its stability
C. Is the same for set point or load changes
D. All of the above

View Answer

Question 294

Thermistors are made of

A. Ultra pure metals
B. Metal oxides
C. Iron-copper alloys
D. Nickel-chromium alloys

View Answer

Question 295

The unit step response of the transfer function 1/(s² + 2s + 3)

A. Has a non-zero slope at the origin
B. Has a damped oscillatory characteristics
C. Is overdamped
D. Is unstable

View Answer

Question 296

An amplitude ratio of 0.1 corresponds to __________ decibels.

A. 20
B. -20
C. 10
D. -10

View Answer

Question 297

Nickel percentage in invar which is an iron-nickel alloy, and is used as a thermocouple material is

A. 12
B. 36
C. 54
D. 68

View Answer

Question 298

A non-linear system will have __________ steady state values.

A. One
B. More than one
C. Two
D. Three

View Answer

Question 299

Which of the following is an undesirable dynamic characteristic of an instrument?

A. Reproducibility
B. Dead zone
C. Time lag
D. Static error

View Answer

Question 300

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

View Answer

Question 301

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.

View Answer

Question 302

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. 100
C. 10
D. 1

View Answer

Question 303

Continuous shell temperature measurement in a liquid-liquid heat exchanger is done by a

A. thermocouple
B. reistance thermometer
C. mercury in glass thermometer
D. vapor pressure thermometer

View Answer

Question 304

Small furnace draught is accurately measured by an inclined tube manometer, in which the manometric liquid used most commonly is

A. Water
B. Carbon tetrachloride
C. Paraffin
D. Ethylene glycol

View Answer

Question 305

Radiation thermometer can not measure the temperature

A. Inside a pressure vessel
B. Of an object without coming in contact with it
C. Of liquid oxygen
D. Of moving objects at high temperature

View Answer

Question 306

The time constant of a first order process with resistance R and capacitance C is

A. R + C
B. R - C
C. RC
D. 1/RC

View Answer

Question 307

Thermal conductivity measurement com-prises the working principle of a

A. CO2 analyser
B. polarimeter
C. spectrometer
D. chromatograph

View Answer

Question 308

E.m.f. generated by thermocouples is of the order of

A. Millivolts
B. Microvolts
C. Volts
D. Kilo volts

View Answer

Question 309

Dilatometer is used to measure

A. Stress
B. Strain
C. Deflection
D. Contraction/expansion due to changes in temperature

View Answer

Question 310

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

View Answer

Question 311

A mercury thermometer can not be used to measure the temperature below the freezing point of mercury, which is __________ °C.

A. -38.9
B. -11.9
C. -60.9
D. -80.9

View Answer

Question 312

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.

A. No change
B. Decrease
C. Increase
D. Exponential decrease

View Answer

Question 313

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

View Answer

Question 314

Working principle of mercury in glass thermometer is based on the __________ of mercury with increase in temperature.

A. Increase of pressure
B. Increase of thermal conductivity
C. Volumetric expansion
D. Differential linear expansion

View Answer

Question 315

In a feed-back control system G and H denote open loop and close loop transfer functions respectively. The output-input relationship is

A. G/(1 + H)
B. H(1 + G)
C. G/H
D. H/G

View Answer

Question 316

Bimetal strips are not used in

A. Bimetallic thermometers
B. Thermocouples
C. Thermostats
D. Relays for opening & closing of electrical circuits

View Answer

Question 317

Strain gage pressure transducers are used to measure __________ pressures.

A. Gage as well as vacuum
B. Absolute as well as differential
C. Both A & B
D. Neither A nor B

View Answer

Question 318

Which of the following is an undesirable dynamic characteristic of an instrument ?

A. Reproducibility
B. Dead zone
C. Time lag
D. Static error

View Answer

Question 319

Normal mercury thermometer can be used to measure a temperature of about 300°C. However, its maximum temperature measurement range can be increased upto about 500°C by

A. Filling nitrogen under pressure in the stem
B. Increasing the diameter of the tube
C. Using steel tube in place of glass tube
D. Accounting for the tube expansion

View Answer

Question 320

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 the above

View Answer

Question 321

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. O₂
C. NO
D. NO₂

View Answer

Question 322

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 (a), (b) and (c).

View Answer

Question 323

A sinusoidal variation in the input passing through a linear first order system

A. Becomes more oscillatory (frequency increases)
B. Becomes less oscillatory (frequency decreases)
C. Gets amplified (magnitude increases)
D. Gets attenuated (magnitude decreases)

View Answer

Question 324

Polarisation of light forms the working principle of a

A. Polarimeter
B. Polarograph
C. Chromatograph
D. Spectrometer

View Answer

Question 325

Which of the following thermocouple materials does not contain nickel?

A. Alumel
B. Chromel
C. Constantan
D. None of these

View Answer

Question 326

Working principle of mercury in glass thermometer is based on volumetric expansion of mercury with increase in temperature. Which of the following undergoes minimum volumetric expansion for a given temperature change?

A. Water
B. Mercury
C. Methyl alcohal
D. Carbon-tetrachloride

View Answer

Question 327

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. Nyquist
C. Routh stability
D. None of these

View Answer

Question 328

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

View Answer

Question 329

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)

View Answer

Question 330

The offset introduced by proportional controller with gain Kc in response of first order system can be reduced by

A. Reducing value of Kc
B. Introducing integral control
C. Introducing derivative control
D. None of the above

View Answer

Question 331

Which of the following is a 'contact' pyrometer?

A. Resistance pyrometer
B. Optical pyrometer
C. Radiation pyrometer
D. Infra red pyrometer

View Answer

Question 332

Which of the following instruments is not used for measuring sub-zero (<0°) temperatures?

A. Platinum resistance thermometer
B. Mercury in glass thermometer
C. Vapor pressure thermometer
D. Radiation pyrometer

View Answer

Question 333

Turbine flow meters are suitable for

A. Very limited flow ranges
B. Cryogenic flow measurements
C. Aerospace and in air borne applications
D. Both B and C

View Answer

Question 334

Which of the following fluid flow measuring devices can measure the largest flow rate?

A. V-notch
B. Rotameter
C. Orificemeter
D. Weir

View Answer

Question 335

Which of the following thermocouples can measure the maximum temperature?

A. Platinum-rhodium
B. Tungsten-molybdenum
C. Chromel-alumel
D. Iron-constantan

View Answer

Question 336

Change of angle of refraction with composition comprises the working principle of a

A. Polarimeter
B. Polarograph
C. Spectrometer
D. Refractrometer

View Answer

Question 337

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

View Answer

Question 338

Which of the following thermocouples is capable of measuring a temperature of -50°C?

A. Platinum - platinum + rhodium
B. Chromel - alumel
C. Iron-constantan
D. Copper - constantan

View Answer

Question 339

Stability of a control system containing a transportation lag can be best analysed by

A. Routh test
B. Root locus methods
C. Frequency response methods
D. None of these

View Answer

Question 340

Resistance of a gas in a vessel is given by (where, P = pressure, V = volume of the vessel, n = no. of moles of the gas, R = gas constant)

A. V/nRT
B. nRT/V
C. nRT/P
D. p/nRT

View Answer

Question 341

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. Criterion is not applicable to systems with polynomial characteristic equation
D. Can not determine as to how many roots of the characteristics equation have positive real roots

View Answer

Question 342

Platinum resistance thermometer can be used upto antimony point which is __________ °C, and is the temperature of equilibrium between solid antimony & liquid antimony at normal atmospheric pressure.

A. 961.93
B. 630.74
C. 1064.43
D. 1261.93

View Answer

Question 343

pH meter has

A. One cell
B. Two cells
C. Three cells
D. No cell

View Answer

Question 344

A proportional controller with a gain of Kc is used to control a first order process. The offset will increase, if

A. Kc is reduced
B. Kc is increased
C. Integral control action is introduced
D. Derivative control action is introduced

View Answer

Question 345

Which of the following is not the triple point of water?

A. 32°R
B. 273°K
C. 492°R
D. 32°F

View Answer