MCQOPTIONS
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MCQOPTIONS
This section includes 425 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. |
The unit of conductance in SI unit is_______________? |
| A. | W/m |
| B. | W/m2 |
| C. | W/°K |
| D. | W/m°K |
| Answer» D. W/m°K | |
| 52. |
The type of liquor circulation system to be ‘ employed in evaporators (viz. natural or forced circulation) is determined mainly by the ______________ of the liquid? |
| A. | Viscosity |
| B. | Density |
| C. | Thermal conductivity |
| D. | Corrosive nature |
| Answer» B. Density | |
| 53. |
The thickness of condensate layer in filmwise condensation depends on the__________________? |
| A. | Condensation rate |
| B. | Surface configuration |
| C. | Liquid flow rate from the surface |
| D. | All A., B. and C. |
| Answer» E. | |
| 54. |
The thermal radiative flux from a surface of emissivity = 0.4 is 22.68 kW/m2. The approximate surface temperature (K) is (Stefan-Boltzmann constant = 5.67 × 10-8 W/m2.K4) ? |
| A. | 1000 |
| B. | 727 |
| C. | 800 |
| D. | 1200 |
| Answer» B. 727 | |
| 55. |
The thermal radiation emitted by a body is proportional to Tn, where T is its absolute temperature. The value of ‘n’ is exactly 4 for__________________? |
| A. | Black painted bodies only |
| B. | All bodies |
| C. | Polished bodies only |
| D. | A black body |
| Answer» C. Polished bodies only | |
| 56. |
The thermal efficiency of a reversible heat engine operating between two given thermal reservoirs is 0.4. The device is used either as a refrigerator or as a heat pump between the same reservoirs. Then the coefficient of performance as a refrigerator (COP)R and the co-efficient of performance as a heat pump (COP)HP are _______________? |
| A. | (COP)R = (COP)HP = 0.6 |
| B. | (COP)R = 2.5; (COP)HP = 1.5 |
| C. | (COP)R = 1.5; (COP)HP = 2.5 |
| D. | (COP)R = (COP)HP = 2.5 |
| Answer» D. (COP)R = (COP)HP = 2.5 | |
| 57. |
The thermal boundary layer at NPr > 1 ? |
| A. | Is thicker than hydrodynamic boundary layer |
| B. | Is thinner than hydrodynamic boundary layer |
| C. | And the hydrodynamic boundary layers are identical |
| D. | Disappears |
| Answer» C. And the hydrodynamic boundary layers are identical | |
| 58. |
The sum of reflectivity and absorptivity for an opaque body is equal to____________________? |
| A. | 0.5 |
| B. | 1 |
| C. | 0 |
| D. | 2 |
| Answer» C. 0 | |
| 59. |
The Stefan-Boltzmann constant depends on the_________________? |
| A. | Medium |
| B. | Temperature |
| C. | Surface |
| D. | None of these |
| Answer» E. | |
| 60. |
The steam ejector is used to__________________? |
| A. | Remove condensate from the steam pipelines |
| B. | Create vacuum |
| C. | Superheat the steam |
| D. | None of these |
| Answer» C. Superheat the steam | |
| 61. |
The statement that “maximum wavelength of radiation is inversely proportional to the temperature” is ______________ law? |
| A. | Stefan-Boltzmann’s |
| B. | Planck’s |
| C. | Wien’s displacement |
| D. | None of these |
| Answer» D. None of these | |
| 62. |
The Sieder-Tate correlation for heat transfer in turbulent flow in pipe gives Nu α Re0.8, where, Nu is the Nusselt number and Re is the Reynolds number for the flow. Assuming that this relation is valid, the heat transfer co-efficient varies with the pipe diameter D. as _________________? |
| A. | D-1.8 |
| B. | D-0.2 |
| C. | D0.2 |
| D. | D1.8 |
| Answer» C. D0.2 | |
| 63. |
The separation of liquid droplets from the vapor is done by a/an _____________ in the evaporators? |
| A. | Steam ejector |
| B. | Entrainment separator |
| C. | Compressor |
| D. | Vacuum pump |
| Answer» C. Compressor | |
| 64. |
The ratio of velocity head to tube side return loss in case of a multipass shell and tube heat exchanger is ________________? |
| A. | 2 |
| B. | 1/2 |
| C. | 4 |
| D. | 1/4 |
| Answer» E. | |
| 65. |
The ratio of total radiating power to the absorptivity of the body depends upon the _____________ as per Kirchoff‟s law? |
| A. | Wavelength of radiation |
| B. | Nature of the body |
| C. | Temperature of the body |
| D. | None of these |
| Answer» D. None of these | |
| 66. |
“The ratio of the total emissive power to the absorptivity for all bodies is same at ther-mal equilibrium”. This is ______________ law? |
| A. | Kirchoff’s |
| B. | Planck’s |
| C. | Wien’s displacement |
| D. | Stefan-Boltzmann |
| Answer» B. Planck’s | |
| 67. |
The ratio of momentum diffusivity to thermal diffusivity is the ______________ number? |
| A. | Prandtl |
| B. | Nusselt |
| C. | Stanton |
| D. | Grashoff |
| Answer» B. Nusselt | |
| 68. |
The ratio of kinematic viscosity to thermal diffusivity is called the _______________ number? |
| A. | Peclet |
| B. | Prandtl |
| C. | Stanton |
| D. | Nusselt |
| Answer» C. Stanton | |
| 69. |
The rate of heat transfer is a product of overall heat transfer co-efficient, the difference in temperature and the___________________? |
| A. | Heating volume |
| B. | Heat transfer area |
| C. | Nusselt number |
| D. | None of these |
| Answer» C. Nusselt number | |
| 70. |
The rate of heat transfer through a pipe wall is given by, q = 2π k (Ti – T0)/ln (ri/r0). For cylinder of very thin wall, q can be approximated by__________________? |
| A. | q = [2π k (Ti + T0)/2]/ln (ri/r0) |
| B. | q = 2π ri k (Ti – T0)/(r0/ri) |
| C. | q = 2π k (Ti – T0)/(r0/ri) |
| D. | q = 2π k (Ti – T0)/[(r0 + ri)/2] |
| Answer» E. | |
| 71. |
The rate of heat transfer from a vertical plate by natural convection depends upon the temperature differences (ΔT) between wall and outside bulk. The proportionality is given as______________? |
| A. | (ΔT)1/4 |
| B. | (ΔT)1/2 |
| C. | (ΔT)5/4 |
| D. | (ΔT)3/4 |
| Answer» E. | |
| 72. |
The rate of emission of radiation by a body does not depend upon the__________________? |
| A. | Wavelength of radiation |
| B. | Surface temperature of the body |
| C. | Nature of the surface |
| D. | Shape and porosity of the body |
| Answer» E. | |
| 73. |
The range of electromagnetic spectrum important in heat transfer by radiation is ______________ microns? |
| A. | 0.38-0.78 |
| B. | 0.5-50 |
| C. | 100-1000 |
| D. | 5-50 |
| Answer» C. 100-1000 | |
| 74. |
The radiation heat flux from a heating element at a temperature of 800°C, in a furnace maintained at 300°C is 8 kW/m2. The flux, when the element temperature is increased to 1000°C for the same furnace temperature is_____________________? |
| A. | 11.2 kW/m2 |
| B. | 12.0 kW/m2 |
| C. | 14.6 kW/m2 |
| D. | 16.5 kW/m2 |
| Answer» E. | |
| 75. |
The purpose of providing expansion bellows in the shell of tubular exchanger is to _____________________? |
| A. | Increase the heating load |
| B. | Impart structural strength |
| C. | Account for the uneven expansion of shell and tube bundles |
| D. | Facilitate increase of shell length, if needed |
| Answer» D. Facilitate increase of shell length, if needed | |
| 76. |
The purpose of providing bleed points in the evaporator is to__________________? |
| A. | Admit the feed |
| B. | Remove the product |
| C. | Facilitate removal of non-condensable gases |
| D. | Create vacuum |
| Answer» D. Create vacuum | |
| 77. |
The purpose of providing a ‘catchall’ in the vapor line of an evaporator is to__________________? |
| A. | Create vacuum |
| B. | Regulate the vapor flow |
| C. | Vent the non-condensable gases |
| D. | Arrest the entrained liquid |
| Answer» E. | |
| 78. |
The overall resistance for heat transfer through a series of flat resistance, is the _____________ of the resistances? |
| A. | Average |
| B. | Geometric mean |
| C. | Product |
| D. | Sum |
| Answer» E. | |
| 79. |
The overall heat transfer co-efficient for a shell and tube heat exchanger for clean surfaces is U0 = 400 W/m2.K. The fouling factor after one year of operation is found to be hd0 = 2000 W/m2.K. The overall heat transfer co-efficient at this time is _____________________? |
| A. | 1200 W/m2.K |
| B. | 894 W/m2.K |
| C. | 333 W/m2.K |
| D. | 287 W/m2.K |
| Answer» D. 287 W/m2.K | |
| 80. |
The Nusselt number for fully developed (both thermally and hydrodynamically) laminar flow through a circular pipe whose surface temperature remains constant is______________? |
| A. | 1.66 |
| B. | 88.66 |
| C. | 3.66 |
| D. | Dependent on NRe only |
| Answer» D. Dependent on NRe only | |
| 81. |
The Nusselt number for fully developed (both thermally and hydrodynamically) laminar flow through a circular pipe, where the wall heat flux is constant, is__________________? |
| A. | 2.36 |
| B. | 4.36 |
| C. | 120.36 |
| D. | Dependent on NRe only |
| Answer» C. 120.36 | |
| 82. |
The number of kg vaporised per kg of steam fed to the evaporator is defined as____________? |
| A. | Capacity |
| B. | Rate of evaporation |
| C. | Economy |
| D. | Rate of vaporisation |
| Answer» D. Rate of vaporisation | |
| 83. |
The non-dimensional temperature gradient in a liquid at the wall of a pipe is the ____________________? |
| A. | Heat flux |
| B. | Nusselt number |
| C. | Prandtl number |
| D. | Schmidt number |
| Answer» B. Nusselt number | |
| 84. |
The most conducive surface for dropwise condensation to occur is the _____________ surface? |
| A. | Coated |
| B. | Oily |
| C. | Glazed & polished |
| D. | Smooth |
| Answer» C. Glazed & polished | |
| 85. |
The maximum heat transfer co-efficient from steam heating will be attained when the steam is_________________? |
| A. | Supersaturated |
| B. | Saturated |
| C. | Wet |
| D. | None of these |
| Answer» C. Wet | |
| 86. |
The main purpose of providing fins on heat transfer surface is to increase the_________________? |
| A. | Temperature gradient |
| B. | Mechanical strength of the equipment |
| C. | Heat transfer area |
| D. | Heat transfer co-efficient |
| Answer» D. Heat transfer co-efficient | |
| 87. |
The main function of baffles provided in a shell and tube heat exchanger is to______________? |
| A. | Facilitate the cleaning of outer tube surface |
| B. | Enhance turbulence |
| C. | Hold the tubes in position |
| D. | All A , B & C |
| Answer» C. Hold the tubes in position | |
| 88. |
The left face of a one dimensional slab of thickness 0.2 m is maintained at 80°C and the right face is exposed to air at 30°C. The thermal conductivity of the slab is 1.2 W/m.K and the heat transfer co-efficient from the right face is 10 W/m2.K. At steady state, the temperature of the right face in °C is____________________? |
| A. | 77.2 |
| B. | 71.2 |
| C. | 63.8 |
| D. | 48.7 |
| Answer» E. | |
| 89. |
The interchange factor for radiation heat transfer from surface ‘x’ to surface ‘y’ in case of an infinite parallel planes with emissivities εx & εy is given by_______________? |
| A. | εx + εy |
| B. | εx . εy |
| C. | 1/εx + 1/εy |
| D. | (εx + εy)/( εx + εy – εx . εy) |
| Answer» E. | |
| 90. |
The inside heat transfer co-efficient in case of turbulent flow of liquid in the tube side in a 1-2 shell and tube heat exchanger is increased by ______________ times, when the number of tube passes is increased to 8? |
| A. | 20.8 |
| B. | 40.8 |
| C. | 40.4 |
| D. | 20.4 |
| Answer» C. 40.4 | |
| 91. |
The inner wall of a furnace is at a temperature of 700°C. The composite wall is made of two substances, 10 and 20 cm thick with thermal conductivities of 0.05 and 0.1 W.m-1.°C- 1 respectively. The ambient air is at 30°C and the heat transfer co-efficient between the outer surface of wall and air is 20 W.m-2.°C-1. The rate of heat loss from the outer surface in W.m-2is__________________? |
| A. | 165.4 |
| B. | 167.5 |
| C. | 172.5 |
| D. | 175 |
| Answer» B. 167.5 | |
| 92. |
The heat transfer co-efficient in film type condensation is _______________ that for dropwise condensation? |
| A. | Greater than |
| B. | Lower than |
| C. | Is same as |
| D. | Half |
| Answer» C. Is same as | |
| 93. |
The heat transfer by radiation from a mild steel surface is to be reduced by reducing the emissivity of the surface. This can be best achieved by__________________? |
| A. | Painting the surface black |
| B. | Painting the surface white (with aluminium paint) |
| C. | Giving the surface a mirror finish |
| D. | Roughening the surface |
| Answer» C. Giving the surface a mirror finish | |
| 94. |
The heat flux in the nucleate boiling regimes is proportional to (where, ΔT = excess temperature) ? |
| A. | (ΔT)2 |
| B. | (ΔT)4 |
| C. | (ΔT)3 |
| D. | √(ΔT) |
| Answer» D. √(ΔT) | |
| 95. |
The heat flux (from outside to inside) across an insulating wall with thermal conductivity, K = 0.04 W/m.°K and thickness 0.16m is 10 W/m2. The temperature of the inside wall is – 5°C. The outside wall temperature is___________________? |
| A. | 25°C |
| B. | 30°C |
| C. | 35°C |
| D. | 40°C |
| Answer» D. 40°C | |
| 96. |
The Graetz number is concerned with the___________________ |
| A. | Mass transfer between a gas and a liquid |
| B. | Absorption with chemical reaction |
| C. | Heat transfer in turbulent flow |
| D. | Heat transfer in laminar flow |
| Answer» E. | |
| 97. |
The film thickness for laminar film condensation on vertical surface _____________ from top to bottom? |
| A. | Cumulatively increases |
| B. | Cumulatively decreases |
| C. | Remain constant |
| D. | And the surface conductance increase |
| Answer» B. Cumulatively decreases | |
| 98. |
The film co-efficient is decreased due to the presence of non-condensing gases in the vapors. The film co-efficient of superheated vapor as compared to that of saturated vapor is___________________? |
| A. | More |
| B. | Less |
| C. | Some |
| D. | Either more or less; depends on the nature of vapor |
| Answer» D. Either more or less; depends on the nature of vapor | |
| 99. |
The film co-efficient between condensing vapour and metal wall increases with _____________________? |
| A. | Increasing temperature of the vapour |
| B. | Decreasing temperature of the vapour |
| C. | Increasing viscosity of the film of condensate |
| D. | Increasing temperature drop |
| Answer» B. Decreasing temperature of the vapour | |
| 100. |
The equivalent diameter for the annulus of a double pipe heat exchanger, whose inner pipe has fins on the outside is ______________ compared to the same size pipes without fins? |
| A. | More |
| B. | Less |
| C. | Same |
| D. | Unpredictable |
| Answer» C. Same | |