MCQOPTIONS
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MCQOPTIONS
This section includes 830 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
In Bode plot, Φ vs ω is plotted on a/an __________ graph paper. |
| A. | log-log |
| B. | ordinary |
| C. | semi-log |
| D. | triangular |
| Answer» B. ordinary | |
| 52. |
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. |
| Answer» B. increasing the diameter of the tube. | |
| 53. |
A control system has the following transfer functionThe initial value of the corresponding time function is |
| A. | 1 |
| B. | 1/8 |
| C. | 7/8 |
| D. | -1 |
| Answer» B. 1/8 | |
| 54. |
The root locus plot of the roots of the characteristics equation of a closed loop system having the open loop transfer function will have a definite num-ber of loci for variation of from 0 to ∞. The number of loci is |
| A. | 1 |
| B. | 3 |
| C. | 4 |
| D. | 2 |
| Answer» C. 4 | |
| 55. |
Silver point temperature is __________ °C. |
| A. | 760.5 |
| B. | 860.5 |
| C. | 960.5 |
| D. | 1060.5 |
| Answer» D. 1060.5 | |
| 56. |
What is the Laplace transform of impulse input having magnitude '' ? |
| A. | 1/ |
| B. | 1 |
| Answer» E. | |
| 57. |
When the damping co-efficient (ξ) is unity, the system is |
| A. | Overdamped. |
| B. | Critically damped. |
| C. | Underdamped. |
| D. | Highly fluctuating. |
| Answer» C. Underdamped. | |
| 58. |
Compositional analysis of flue gas coming out of a furnace in respect of O and CO% can be continuously done by a/an |
| A. | orsat apparatus |
| B. | thermal conductivity cell |
| C. | zirconia probe |
| D. | chromatograph |
| Answer» C. zirconia probe | |
| 59. |
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 |
| Answer» B. nitrogen | |
| 60. |
Liquid column manometers are used for measuring the pressure __________ kgf/cm . |
| A. | > 2(gage) |
| B. | < 3 (gage) |
| C. | < 10 (gage) |
| D. | < atmospheric |
| Answer» C. < 10 (gage) | |
| 61. |
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). |
| Answer» E. | |
| 62. |
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. |
| Answer» E. | |
| 63. |
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 |
| Answer» C. 1064.43 | |
| 64. |
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 |
| Answer» B. Chromel - alumel | |
| 65. |
The inverse Laplace transform of the function is |
| A. | 1 + e |
| B. | 1 - e |
| C. | 1 + e |
| D. | 1 - e |
| Answer» E. | |
| 66. |
The experimental response of the controlled variable y(t) for a step change of magnitude P in the manipulated variable x(t) is shown below :The appropriate transfer function of the process is |
| A. | [A]. |
| B. | [B]. |
| C. | [C]. |
| D. | [D]. |
| Answer» D. [D]. | |
| 67. |
A process is initially at steady state with its output y=l for an input u=l. The input is suddenly changed to 2 at time t=0. The output response is y(t)=1+2t. The transfer function of the process is |
| A. | 2/s |
| B. | [B]. |
| C. | [C]. |
| D. | [D]. |
| Answer» E. | |
| 68. |
The root locus plot of the roots of the characteristics equation of a closed loop system having the open loop transfer function will have a definite num-ber of loci for variation of K from 0 to ∞. The number of loci is |
| A. | 1 |
| B. | 3 |
| C. | 4 |
| D. | 2 |
| Answer» C. 4 | |
| 69. |
The transfer function for a PID controller is (where, τ i is the integral (reset) time and τD is the derivative time.) |
| A. | Kc(1 + τis + τD ). s |
| B. | [B]. |
| C. | [C]. |
| D. | [D]. |
| Answer» C. [C]. | |
| 70. |
What is the overall transfer function (C/R) of the following block diagram if G = G1. G2. G3 and H = H1.H2. |
| A. | [A]. |
| B. | [B]. |
| C. | [C]. |
| D. | [D]. |
| Answer» C. [C]. | |
| 71. |
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. | , 0.6, 0.08 |
| B. | 2, 0.6, 0.12 |
| C. | , 0.6, 0.12 |
| D. | 2, 0.4, 0.08 |
| Answer» C. , 0.6, 0.12 | |
| 72. |
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. | ater |
| B. | ercury |
| C. | ethyl alcohal |
| D. | arbon-tetrachloride |
| Answer» C. ethyl alcohal | |
| 73. |
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. | O₂ |
| B. | ₂ |
| C. | O |
| D. | O₂ |
| Answer» B. ₂ | |
| 74. |
Which of the following relates the emf. generated in a single homogeneous wire to the temperature difference? |
| A. | eltier effect |
| B. | homson effect |
| C. | eebeck effect |
| D. | one of these |
| Answer» C. eebeck effect | |
| 75. |
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. | verdamped response |
| B. | nderdamped response |
| C. | ndamped response |
| D. | nstable response |
| Answer» C. ndamped response | |
| 76. |
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. | O₂ |
| B. | ₂ |
| C. | ₂ |
| D. | O |
| Answer» B. ₂ | |
| 77. |
Which of the following shows maximum dip effect (indicating reverse direction of temperature change)? |
| A. | ercury thermometer |
| B. | adiation pyrometer |
| C. | imetallic thermometer |
| D. | hermocouple |
| Answer» B. adiation pyrometer | |
| 78. |
Which of the following does not figure in the list of seven substances selected for international temperature scale? |
| A. | ce (F.P) and steam (B.P) |
| B. | xygen and sulphur (B.P) |
| C. | ntimony and silver (F.P) |
| D. | inc (B.P) and mercury (F.P) |
| Answer» E. | |
| 79. |
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. | H meter |
| B. | olarimeter |
| C. | hromatograph |
| D. | olarograph |
| Answer» B. olarimeter | |
| 80. |
Which of the following filled system expansion thermometer has the capability to measure the lowest temperature? |
| A. | ercury in glass thermometer |
| B. | ercury in steel thermometer |
| C. | lcohol in glass thermometer |
| D. | used metal (Na or K) in steel thermometer |
| Answer» D. used metal (Na or K) in steel thermometer | |
| 81. |
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. |
| Answer» C. introducing derivative control. | |
| 82. |
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 |
| Answer» C. 8, 0.6, 0.12 | |
| 83. |
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 |
| Answer» B. Iron-constantan | |
| 84. |
The second order system with the transfer function 4 / (s²+2s+4) has a damping ratio of |
| A. | 2.0 |
| B. | 0.5 |
| C. | 1.0 |
| D. | 4.0 |
| Answer» C. 1.0 | |
| 85. |
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 |
| Answer» B. critically damped | |
| 86. |
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 |
| Answer» C. G/H | |
| 87. |
The inverse Laplace transform of the function f(s) = 1 / S(1+S) is |
| A. | 1 + eᵗ |
| B. | 1 - eᵗ |
| C. | 1 + eᵗ |
| D. | 1 - e⁻ᵗ |
| Answer» E. | |
| 88. |
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) |
| Answer» B. level | |
| 89. |
Number of poles in a system with transfer function 1 / (s²+2s²+1) is |
| A. | 2 |
| B. | 5 |
| C. | 3 |
| D. | 1 |
| Answer» D. 1 | |
| 90. |
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. |
| Answer» B. dead time system. | |
| 91. |
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 |
| Answer» D. Copper-constantan | |
| 92. |
A system with transfer function 2S/4S + 1 is of __________ order. |
| A. | zero |
| B. | 1st |
| C. | 2nd |
| D. | 3rd |
| Answer» C. 2nd | |
| 93. |
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 |
| Answer» E. | |
| 94. |
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 |
| Answer» E. | |
| 95. |
On-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 |
| Answer» E. | |
| 96. |
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 |
| Answer» C. radiation pyrometer | |
| 97. |
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. | overdamped response. |
| B. | underdamped response. |
| C. | undamped response. |
| D. | unstable response. |
| Answer» C. undamped response. | |
| 98. |
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 |
| Answer» C. zirconia probe | |
| 99. |
Find the Laplace transform of the following input function shown in figure. |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 100. |
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 1 |
| B. | Tank 2 |
| C. | Tank 3 |
| D. | Tank 4 |
| Answer» D. Tank 4 | |