chemical engineering process control and instrumentation Mcqs
51. Thermal conductivity cell is the primary element of a/an _____________ analyser?
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A. Oxygen

B. Carbon dioxide

C. Carbon monoxide

D. Sulphur dioxide

52. Phase lag of the sinusoidal response of a first order system is _________________?
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A. 30

B. 120

C. 180

D. 90
53. 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______________?
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A. -90

B. -45

C. -180

D. 45

54. Measurement of sub-zero Celsius temperature in industry is done most commonly by __________________?
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A. Thermocouples

B. Gas thermometers

C. Resistance thermometers

D. Bi-metallic thermometers

55. Range of hydrogen gas constant volume thermometer is _____________ C?
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A. -10 to 20

B. 400 1000

C. 0 to 100

D. 100 500

56. If response of a control system is to be free of offset and oscillation, the most suitable controller is_________________?
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A. Proportional-integral (PI) controller

B. Proportional controller

C. Proportional-derivative (PD) controller

D. Proportional integral-derivative (PID) controller
57. Flow rate measurement of hostile acids and alkalis can be most suitably done by a/an ________________?
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A. Hot wire anemometer

B. Venturimeter

C. Orificemeter

D. Magnetic flow meter
58. Which of the following is never used as an element of industrial resistance thermometer ?
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A. Nickel

B. 30% iron + 70% nickel

C. Copper

D. Lead
59. 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?
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A. Tank 2

B. Tank 3

C. Tank 1

D. Tank 4

60. Typical specifications for design stipulates the gain margin and phase margin to be respectively__________________?
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A. 30

B. > 1.7 and > 30

C. < 1.7 and 1.7 and < 30

61. The unit step response of the transfer function (2s 1)/[(3s + 1) (4s + 1)] reaches its final steady state asymptotically after _____________?
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A. A monotonic decrease

B. A monotonic increase

C. Initially increasing and then decreasing

D. Increasing decreasing and then increasing

62. Bourdon tube is never made of________________?
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A. Monel metal

B. Cast iron

C. Stainless steel

D. Phosphor bronze

63. Conversion formula for converting amplitude ratio (AR) into decibels is ________________?
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A. Decibel = 20 log10 (AR)0.5

B. Decibel = 20 log10 (AR)

C. Decibel = 20 loge (AR)

D. Decibel = 20 loge (AR)0.5

64. Routh test_________________?
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A. Criterion is not applicable to systems with polynomial characteristic equation

B. Criterion provides information about the actual location of roots

C. Cannot be used to test the stability of a control system containing transportation lag

D. Cannot determine as to how many roots of the characteristics equation have positive real roots

65. Which of the following is not a variable area flow meter ?
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A. Orifice and tapered plug meter

B. Piston type meter

C. Magnetic flow meter

D. Rotameter

66. Reference points i.e., ice point and steam point in Reaumer temperature scale are respectively_________________?
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A. 273 & 80

B. 32 & 460

C. 0 & 80

D. 32 & 80

67. The closed loop pole of a stable second order system could be_______________?
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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

68. The response of two tanks of same size and resistance in series is __________________?
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A. Over damped

B. Under damped

C. Critically damped

D. None of the above

69. Pirani gauge is used for the measurement of________________?
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A. Very high pressure

B. Liquid level at atmospheric pressure

C. Liquid level under pressure

D. High vacuum
70. Maximum differential pressure in liquid manometer is ______________ psi?
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A. 20

B. 50

C. 40

D. 30
71. A stable system is the one___________________?
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A. Which satisfies the conditions for a servo problem

B. For which the output response is bounded for all bounded input

C. None of these

D. Which exhibits an unbounded response to a bounded input

72. High temperature of around 2000C of incandescent gas mantles is measured by a/an __________________?
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A. Specially designed thermocouple

B. Optical pyrometer

C. Radiation pyrometer

D. None of these

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

B. 2 AT

C. 0.5 AT

D. 1.5 AT

74. Which of the following thermocouples has the widest temperature measurement range ?
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A. Chromel-alumel

B. Copper-constantan

C. Iron-constantan

D. Platinum-platinum/rhodium
75. In a shell and tube heat exchanger, the flow rate of heating/cooling fluid is the ______________ variable?
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A. None of these

B. Manipulated

C. Load

D. Controlled

76. Polarograph is meant for the analysis of __________________?
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A. Miscible liquids

B. Isotopes

C. Gaseous mixture

D. Solids
77. The ______________ of a vapor pressure thermometer is a primary element?
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A. Bourdon tube

B. Pointer

C. Bulb

D. None of these

78. Presence of a small amount of water in the organic systems can be determined by the _____________ method?
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A. Polarimetry

B. Dielectric constant end loss factor

C. Electrical conductivity

D. Emission spectroscopy

79. Magnetic flowmeters are generally not used for the velocity/flow measurement of hydrocarbons due to their ?
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A. Low thermal conductivity

B. High viscosity index

C. Low flash point

D. Low electrical conductivity
80. In second order underdamped system ?
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A. Decay ratio = overshoot

B. Decay ratio = (overshoot)2

C. Large damping co-efficient means smaller damping

D. Overshoot increases for increasing damping co-efficient

81. Which is the most suitable instrument for measuring pressure below 3 microns ?
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A. Mcleod gauge

B. Alphatron

C. Bourdon gauge

D. Ionisation gauge
82. Which of the following thermocouples can measure the maximum temperature ?
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A. Chromel-alumel

B. Platinum-rhodium

C. Tungsten-molybdenum

D. Iron-constantan

83. Polarisation of light forms the working principle of a______________?
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A. Polarimeter

B. Spectrometer

C. Chromatograph

D. Polarograph

84. Which of the following filled system expansion thermometer has the capability to measure the lowest temperature ?
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A. Mercury in steel thermometer

B. Mercury in glass thermometer

C. Alcohol in glass thermometer

D. Fused metal (Na or K) in steel thermometer

85. In a shell and tube heat exchanger, the outlet temperature of heating/cooling fluid is the _____________ variable?
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A. None of these

B. Manipulated

C. Controlled

D. Load

86. Transfer function of transportation lag is___________________?
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A. None of these

B. 1/(Ts + 1)

C. eTS

D. e-TS
87. Degree to which an instrument indicates the changes in measured variable without dynamic error is called its ___________________?
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A. Reproducibility

B. Static characteristics

C. Fidelity

D. Speed of response

88. Mass spectrometer is used for the composition analysis of____________________?
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A. None of these

B. Solids

C. Isotopes

D. Alloys

89. Flow rate through an orifice is _____________ the pressure differential?
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A. Proportional to the square root of

B. Proportional to

C. Inversely proportional to the square root of

D. Inversely proportional to the square of

90. For two non-interacting first order systems connected in series, the overall transfer function is the ______________ of the individual transfer functions?
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A. Difference

B. Ratio

C. Sum

D. Product
91. Thermal well made of _____________ gives the fastest speed of response, while measuring temperature by thermocouples?
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A. Steel

B. Vycor (a glass)

C. Nichrome

D. Inconel

92. Small furnace draught is accurately measured by an inclined tube manometer, in which the manometric liquid used most commonly is __________________?
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A. Ethylene glycol

B. Water

C. Paraffin

D. Carbon tetrachloride

93. ____________ are analysed using a Polarograph?
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A. Solids

B. Gases

C. Liquids

D. Isotonic solutions

94. Which of the following is a contact pyrometer ?
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A. Optical pyrometer

B. Infra red pyrometer

C. Resistance pyrometer

D. Radiation pyrometer

95. Which of the following thermometers is not suitable for distant reading upto 60 metres ?
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A. Mercury in glass thermometer

B. Constant volume gas thermometer

C. Vapor pressure thermometer

D. Resistance thermometer

96. The amplitude ratio for the sinusoidal response of a _____________ is 1?
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A. Second order system

B. None of these

C. First order system

D. Transportation lag
97. Which of the following is not a mechanical pressure sensing element ?
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A. Bourdon tube

B. Bellows

C. Diaphragm

D. U-tube
98. Which of the following flow-metering instruments is an areameter ?
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A. Venturimeter

B. Rotameter

C. Hot wire anemometer

D. Pitot tube

99. 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________________?
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A. 0.2/0.5

B. 0.5/0.2

C. 0.2 0.5

D. 1/?(0.2 0.5)
100. Pick out the most suitable instrument for measuring temperature in the range of-40 to 425C ?
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A. Mercury thermometer

B. Bimetallic thermometer

C. None of these

D. Radiation pyrometer