McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
Chapters
| 51. |
The diameter of fire tubes in Cochran boiler is of the order of |
| A. | 2 cm |
| B. | 6 Cm |
| C. | 8 cm |
| D. | 12 cm |
| Answer» B. 6 Cm | |
| 52. |
In a recuperative air preheater, the heat is transferred |
| A. | from a metal wall from one medium to another |
| B. | from heating an itermediate material and then heating the air from this material |
| C. | by direct mixing , |
| D. | heat is tr |
| Answer» D. heat is tr | |
| 53. |
The function of injector used in small capacity boilers is to |
| A. | create vacuum |
| B. | inject chemical solution in feed pump |
| C. | pump water, similar to boiler feed pump |
| D. | add make up water in the system |
| Answer» C. pump water, similar to boiler feed pump | |
| 54. |
The maximum discharge through a chimney occurs when the height of chimney is |
| A. | infinitely long |
| B. | around 200 meters |
| C. | equal to the height of the hot gas column producing draught |
| D. | outside temperature is very low |
| Answer» C. equal to the height of the hot gas column producing draught | |
| 55. |
The economiser is used in boilers to |
| A. | increase thermal efficiency of boiler |
| B. | economise on fuel |
| C. | extract heat from the exhaust flue gases |
| D. | increase flue gas temperature |
| Answer» A. increase thermal efficiency of boiler | |
| 56. |
An economiser in a boiler |
| A. | increases steam pressure |
| B. | increases steam flow |
| C. | decreases fuel consumption |
| D. | decreases steam pressure |
| Answer» C. decreases fuel consumption | |
| 57. |
The safety valve on boiler drum compared to safety valve on superheater is set at |
| A. | same value |
| B. | higher value |
| C. | lower value |
| D. | lower/higher depending on steam flow |
| Answer» B. higher value | |
| 58. |
The capacity of induced draft fan compared to forced draft fan in a boiler is |
| A. | same |
| B. | more |
| C. | less |
| D. | less or more depending on size of boiler |
| Answer» B. more | |
| 59. |
Evaporative capacity of boiler is expressed as |
| A. | kg of steam produced |
| B. | steam pressure produced |
| C. | kg of fuel fired |
| D. | kg of steam produced per kg of fuel fired |
| Answer» D. kg of steam produced per kg of fuel fired | |
| 60. |
The condition of steam in boiler drum is always |
| A. | dry |
| B. | wet |
| C. | saturated |
| D. | superheated. |
| Answer» B. wet | |
| 61. |
The balanced draft furnace is one using |
| A. | induced draft fan and chimney |
| B. | induced draft fan and forced draft fan |
| C. | forced draft fan and chimney |
| D. | any one of the above |
| Answer» B. induced draft fan and forced draft fan | |
| 62. |
Fire tube boilers are limited to a maximum design working pressure of |
| A. | 1 kg/cm |
| B. | 6 kg/cm |
| C. | 17 kg/cm2 |
| D. | 100 kg/cm2 |
| Answer» C. 17 kg/cm2 | |
| 63. |
For the same diameter and thickness of tube, a water tube boiler compared to a fire tube boiler has |
| A. | more heating surface |
| B. | less heating surface |
| C. | equal heating surface |
| D. | heating surface depends on other parameters |
| Answer» A. more heating surface | |
| 64. |
The feed check valve is used in order to |
| A. | regulate flow of boiler water |
| B. | check level of water in boiler drum |
| C. | recirculate unwanted feed water |
| D. | allow high pressure feed water to flow to drum and not allow reverse flow to take place |
| Answer» D. allow high pressure feed water to flow to drum and not allow reverse flow to take place | |
| 65. |
Equivalent evaporation is the amount of water evaporated in a boiler from and at |
| A. | 0°C |
| B. | 100°C |
| C. | saturation temperature at given pressure |
| D. | room temperature |
| Answer» B. 100°C | |
| 66. |
The equivalent evaporation of a boiler is a measure to compare |
| A. | the given boiler with the model |
| B. | the two different boilers of the same make |
| C. | two different makes of boilers operat¬ing under the same operating conditions |
| D. | any type of boilers operating under any conditions. |
| Answer» D. any type of boilers operating under any conditions. | |
| 67. |
Steam nozzle converts |
| A. | heat energy of steam into pressure energy |
| B. | heat energy of steam into kinetic energy |
| C. | pressure energy of steam into heat energy |
| D. | pressure energy of steam into potential energy |
| Answer» B. heat energy of steam into kinetic energy | |
| 68. |
A nozzle is designed for |
| A. | maximum pressure at the outlet |
| B. | maximum discharge |
| C. | maximum pressure and maximum discharge |
| D. | maximum kinetic energy at the outlet |
| Answer» D. maximum kinetic energy at the outlet | |
| 69. |
Ideal expansion of steam through a nozzle is considered |
| A. | isothermal |
| B. | adiabatic |
| C. | polytropic |
| D. | none of the above |
| Answer» B. adiabatic | |
| 70. |
Presence of frictional effect during flow through the nozzle |
| A. | reduces the exit velocity |
| B. | increases the exit velocity |
| C. | has no effect on exit velocity |
| D. | none of the above |
| Answer» A. reduces the exit velocity | |
| 71. |
Frictional losses in the nozzle |
| A. | reduces the heat drop |
| B. | increases the heat drop |
| C. | has no effect on heat drop |
| D. | none of the above |
| Answer» A. reduces the heat drop | |
| 72. |
While steam expands in turbines, theoretically the entropy |
| A. | remains constant |
| B. | increases |
| C. | decreases |
| D. | behaves unpredictably |
| Answer» A. remains constant | |
| 73. |
Nozzle efficiency is defined as |
| A. | ratio of isentropic heat drop to useful heat drop |
| B. | ratio of useful heat drop to isentropic heat drop |
| C. | product of useful heat drop and isentropic heat drop |
| D. | none of the above |
| Answer» B. ratio of useful heat drop to isentropic heat drop | |
| 74. |
When a nozzle operates with maximum mass flow, it is said to be |
| A. | under expanding flow |
| B. | over expanding flow |
| C. | choked flow |
| D. | none of the above |
| Answer» C. choked flow | |
| 75. |
For supersaturated flow in the nozzle, the discharge |
| A. | increases |
| B. | decreases |
| C. | remains constant |
| D. | none of the above |
| Answer» A. increases | |
| 76. |
For the flow through the convergent and divergent nozzle, whole of friction loss is assumed |
| A. | in the converging portion |
| B. | in the divergent portion |
| C. | between inlet and outlet |
| D. | none of the above |
| Answer» B. in the divergent portion | |
| 77. |
The presence of friction in the nozzle |
| A. | increases the final dryness fraction of steam |
| B. | decreases the final dryness fraction of steam |
| C. | it does not affect the dryness fraction of steam |
| D. | none of the above |
| Answer» A. increases the final dryness fraction of steam | |
| 78. |
When the back pressure of a nozzle is below the critical pressure, the nozzle is said to be |
| A. | under expanding flow |
| B. | over expanding flow |
| C. | choked flow |
| D. | none of the above |
| Answer» C. choked flow | |
| 79. |
Which ideal process is carried out at the turbine in vapour power cycle? |
| A. | reversible adiabatic compression |
| B. | reversible adiabatic expansion |
| C. | reversible constant pressure heat addition |
| D. | reversible constant pressure heat rejection |
| Answer» B. reversible adiabatic expansion | |
| 80. |
The steam turbines is a |
| A. | rotary machine |
| B. | reciprocating machine |
| C. | rotodynamic machine |
| D. | none of the above |
| Answer» C. rotodynamic machine | |
| 81. |
From inlet to exit of steam nozzle, the pressure |
| A. | increases |
| B. | decreases |
| C. | remains constant |
| D. | none of the above |
| Answer» B. decreases | |
| 82. |
From inlet to exit of moving blades in case of impulse turbine, the pressure |
| A. | increases |
| B. | decreases |
| C. | remains constant |
| D. | none of the above |
| Answer» C. remains constant | |
| 83. |
From inlet to exit of moving blades in case of a reaction turbine, the pressure |
| A. | increases |
| B. | decreases |
| C. | remains constant |
| D. | none of the above |
| Answer» B. decreases | |
| 84. |
In an impulse turbine, steam expands |
| A. | in the nozzle only |
| B. | in the moving blades only |
| C. | in the fixed and moving blades |
| D. | none of the above |
| Answer» A. in the nozzle only | |
| 85. |
In a reaction turbine, steam expands |
| A. | in the nozzle only |
| B. | in the moving blades only |
| C. | in the fixed and moving blades |
| D. | none of the above |
| Answer» C. in the fixed and moving blades | |
| 86. |
A simple impulse turbine consists of |
| A. | one set of nozzles and one set of moving blades |
| B. | two sets of nozzle and one set of moving blades |
| C. | one set each of fixed and moving blades |
| D. | none of the above |
| Answer» A. one set of nozzles and one set of moving blades | |
| 87. |
In a velocity-compounded impulse steam turbine, steam expands in |
| A. | one set of nozzles only |
| B. | more than one set of nozzles |
| C. | fixed and moving blades |
| D. | none of the above |
| Answer» A. one set of nozzles only | |
| 88. |
In a pressure-compounded impulse steam turbine, steam expands in |
| A. | nozzles and fixed blades only |
| B. | moving blades only |
| C. | fixed and moving blades both |
| D. | none of the above |
| Answer» A. nozzles and fixed blades only | |
| 89. |
In a pressure-compounded impulse steam turbine, pressure drop over each ring of moving blades |
| A. | remains constant |
| B. | is increasing |
| C. | is decreasing |
| D. | none of the above |
| Answer» A. remains constant | |
| 90. |
In a pressure-compounded impulse steam turbine, as compared to velocity compounding, the number of stages is |
| A. | less |
| B. | more |
| C. | same |
| D. | none of the above |
| Answer» B. more | |
| 91. |
The condensation of steam in a condenser takes place at |
| A. | constant pressure |
| B. | constant temperature |
| C. | constant pressure and constant temperature |
| D. | none of the above |
| Answer» C. constant pressure and constant temperature | |
| 92. |
During condensation process, the temperature of the condensing fluid |
| A. | remains constant |
| B. | decreases |
| C. | increases |
| D. | none of the above |
| Answer» A. remains constant | |
| 93. |
The function of a condenser in a steam power plant is |
| A. | to reduce back pressure |
| B. | to condense the exhaust steam |
| C. | to reduce specific volume of fluid |
| D. | all of the above |
| Answer» D. all of the above | |
| 94. |
In a high-level jet condenser, the condenser shell is installed at a height of |
| A. | more than 5.5 m |
| B. | more than 10.33 m |
| C. | less than 10.33 m |
| D. | none of the above |
| Answer» B. more than 10.33 m | |
| 95. |
The surface condensers are preferred in steam power plant, because |
| A. | they require less coolant |
| B. | condensate can be reused |
| C. | they are more efficient |
| D. | none of the above |
| Answer» B. condensate can be reused | |
| 96. |
In evaporative condensers, the condensing of steam is achieved |
| A. | by rejecting heat to surrounding air |
| B. | by rejecting heat to coolant |
| C. | by evaporation of some coolant |
| D. | none of the above |
| Answer» C. by evaporation of some coolant | |
| 97. |
Dalton's law of partial pressure, applicable to condensers, states that |
| A. | Pa = Pabs + Psat |
| B. | Psat = Pabs + Pa |
| C. | Pabs = Pa+ Psat |
| D. | none of the above |
| Answer» C. Pabs = Pa+ Psat | |
| 98. |
The absolute pressure in a condenser is given by |
| A. | Pabs = Patm + Pvacuum |
| B. | Pabs = Patm -Pvacuum |
| C. | Pabs = Pvacuum |
| D. | none of the above |
| Answer» B. Pabs = Patm -Pvacuum | |
| 99. |
Air leakage into the condenser reduces |
| A. | turbine output |
| B. | cooling capacity |
| C. | life of condenser |
| D. | all of the above |
| Answer» D. all of the above | |
| 100. |
The vacuum maintained in a condenser depends on |
| A. | pressure of cooling water |
| B. | temperature of cooling water |
| C. | back pressure maintained in the condenser |
| D. | all of the above |
| Answer» B. temperature of cooling water | |
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