MCQOPTIONS
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MCQOPTIONS
This section includes 303 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
In arc welding, arc is created between the electrode and work by? |
| A. | contact resistance |
| B. | flow of voltage |
| C. | flow of current |
| D. | electrical energy |
| Answer» E. | |
| 52. |
Consider a situation in which a welding operation is being performed with V = 20 volts, I = 200 A, and the cross-sectional area of the weld bead is 30 mm2. Estimate the welding speed if the workpiece and electrode are made of (a) aluminum, (b) carbon steel, and (c) titanium. Use an efficiency of 75%. |
| A. | 35 mm/s |
| B. | 34.5 mm/s |
| C. | 36 mm/s |
| D. | 46 mm/s |
| Answer» C. 36 mm/s | |
| 53. |
A three phase induction motor is sometimes called a generalized transformer in so far as voltage and frequency transformation has been concerned. Then the rotor emf E2 and the rotor current I2 are zero at |
| A. | ns |
| B. | 2ns |
| C. | zero |
| D. | slip of 50% |
| Answer» B. 2ns | |
| 54. |
A three phase induction motor is sometimes called a generalized transformer in so far as voltage and frequency transformation has been concerned. How a three phase induction motor operates when rotor frequency is less than stator frequency? |
| A. | it operates as induction motor |
| B. | emf is induced in rotor |
| C. | rmf will rotate at synchronous speed |
| D. | all of the mentioned |
| Answer» E. | |
| 55. |
A three phase induction motor is sometimes called a generalized transformer in so far as voltage and frequency transformation has been concerned. How a three phase induction motor operates when rotor frequency is greater than stator frequency? |
| A. | rotor will be driven against rmf |
| B. | rotor will be driven in direction of rmf |
| C. | no emf will be induced |
| D. | the losses will be maximum |
| Answer» B. rotor will be driven in direction of rmf | |
| 56. |
The rotor of a three phase induction motor can never attain synchronous speed. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 57. |
Additives can be used for the non-ferrous application to avoid the poor collapsibility of the mould. |
| A. | true |
| B. | false |
| Answer» C. | |
| 58. |
Co2 moulding is mainly used for the increase in strength and hardness of the moulds and cores. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 59. |
Which of the following types of centrifugal casting process is used for the casting, whose shape of casting is not axi- symmetric? |
| A. | true centrifugal casting |
| B. | semi centrifugal casting |
| C. | centrifuging |
| D. | full centrifugal casting |
| Answer» D. full centrifugal casting | |
| 60. |
Castings made by the centrifugal casting process have negligible porosity. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 61. |
It is also possible to make un-symmetric shape of casting in true centrifugal casting by introducing some variations to the mould. |
| A. | true |
| B. | false |
| Answer» C. | |
| 62. |
Which of the following parts is provided in between the mould and casing to reduce the vibrations? |
| A. | steel balls |
| B. | metallic roller |
| C. | viscous fluid |
| D. | grease |
| Answer» C. viscous fluid | |
| 63. |
Pressure range for low pressure die casting is |
| A. | 0.3-1.5 bars |
| B. | 0.5-2 bars |
| C. | 2-6 bars |
| D. | up to 8 bars |
| Answer» B. 0.5-2 bars | |
| 64. |
Cores used in PMC are usually made up of? |
| A. | metal |
| B. | collapsable material |
| C. | sand |
| D. | all of the mentioned |
| Answer» E. | |
| 65. |
Hollow casting is the other name of which of the following special casting process? |
| A. | slush casting |
| B. | vacuum die casting |
| C. | precision investment casting |
| D. | squeeze casting |
| Answer» B. vacuum die casting | |
| 66. |
The machine used to mix shell mould particles consistently is |
| A. | mixer |
| B. | cupola furnace |
| C. | mueller |
| D. | mixer & cupola furnace |
| Answer» D. mixer & cupola furnace | |
| 67. |
In an induction furnace, mixing and melting rates are altered by? |
| A. | controlling the temperature ranges only |
| B. | controlling the number of electrodes used only |
| C. | controlling power and frequency of current only |
| D. | all of the mentioned factors |
| Answer» D. all of the mentioned factors | |
| 68. |
There is no direct contact of flame and metal in which of the following type of furnace? |
| A. | cupola |
| B. | crucible |
| C. | electric arc |
| D. | induction |
| Answer» C. electric arc | |
| 69. |
Electric arc furnaces are most suitable for which of the following type of material? |
| A. | ferrous |
| B. | non-ferrous |
| C. | both ferrous and nonferrous |
| D. | neither ferrous nor nonferrous |
| Answer» B. non-ferrous | |
| 70. |
The                                property ensures the removal of excess sand in the mould box. |
| A. | adhesiveness |
| B. | cohesiveness |
| C. | green strength |
| D. | compressive strength |
| Answer» B. cohesiveness | |
| 71. |
Binding property of the sand increases because of the                          property. |
| A. | cohesiveness |
| B. | collapsibility |
| C. | flow ability |
| D. | permeability |
| Answer» B. collapsibility | |
| 72. |
The                is responsible for the impact strength in the molding sand. |
| A. | aggregates |
| B. | refractoriness |
| C. | impurities |
| D. | permeability |
| Answer» B. refractoriness | |
| 73. |
Shrinkage allowance does not depend on which of the following factor? |
| A. | moulding method |
| B. | casting dimension |
| C. | pouring temperature of molten metal |
| D. | amount of finish required |
| Answer» E. | |
| 74. |
The initial cost in blow molding is low. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 75. |
°C. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 76. |
What is the maximum thickness that can be allowed for a plastics sheet in a vacuum forming process? |
| A. | 3 mm |
| B. | 3.1 mm |
| C. | 3.2 mm |
| D. | 3.3 mm |
| Answer» D. 3.3 mm | |
| 77. |
Which of the following is not an application of blow molding process? |
| A. | toy bodies |
| B. | door liners |
| C. | bottles |
| D. | pipes |
| Answer» C. bottles | |
| 78. |
Which of the following is not a type of blow molding process? |
| A. | injection blow molding |
| B. | extrusion blow molding |
| C. | multi-smaller blow molding |
| D. | multi-larger blow molding |
| Answer» D. multi-larger blow molding | |
| 79. |
What can be the maximum pressure to be given to plastic for blow molding process? |
| A. | 700 kpa |
| B. | 750 kpa |
| C. | 800 kpa |
| D. | 850 kpa |
| Answer» D. 850 kpa | |
| 80. |
What is the minimum thickness required by the plastic for vacuum forming? |
| A. | 0.125 mm |
| B. | 0.25 mm c) 0.375 mm |
| C. | d) 0.5 mm |
| Answer» B. 0.25 mm c) 0.375 mm | |
| 81. |
What is the minimum air pressure required in the blow molding process? |
| A. | 350 kpa |
| B. | 400 kpa |
| C. | 450 kpa |
| D. | 500 kpa |
| Answer» C. 450 kpa | |
| 82. |
Which of the following plastics is not used in blow molding? |
| A. | terephthalate |
| B. | polypropylene |
| C. | polythene |
| D. | pvc |
| Answer» B. polypropylene | |
| 83. |
In blow molding, to inflate soft plastic, which medium is used? |
| A. | air |
| B. | water |
| C. | oil |
| D. | alcohol |
| Answer» B. water | |
| 84. |
The barrel is used for the opening and closing of the mold. |
| A. | true |
| B. | false |
| Answer» C. | |
| 85. |
What is the minimum pressure allowed to be given to the injection molding process? |
| A. | 90 mpa |
| B. | 100 mpa |
| C. | 140 mpa |
| D. | 170 mpa |
| Answer» C. 140 mpa | |
| 86. |
Which of the following material is not made by injection molding? |
| A. | nuts |
| B. | tubes |
| C. | car handles |
| D. | electrical fittings |
| Answer» C. car handles | |
| 87. |
Thermosetting plastics can be used for manufacturing of windshield for airplane. |
| A. | true |
| B. | false |
| Answer» C. | |
| 88. |
How does the piston in the clamping unit move? |
| A. | hydraulic energy |
| B. | pneumatic energy |
| C. | heat energy |
| D. | suction |
| Answer» B. pneumatic energy | |
| 89. |
How is the die used in injection molding cooled? |
| A. | oil |
| B. | air |
| C. | water |
| D. | contact with cold surface |
| Answer» D. contact with cold surface | |
| 90. |
Mechanical properties of any plastics are mainly dependent on the temperature, force and time of load applied. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 91. |
Phenolic plastics can also be used as binder for holding plies of wood in making of plywood. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 92. |
Polyurethane plastics are highly reactive to chemical compounds due to lack of elasticity in these plastics. |
| A. | true |
| B. | false |
| Answer» C. | |
| 93. |
Thermosetting plastics like epoxies can be used for filament wound rocket motor casings in missiles by combining with glass fibers. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 94. |
Polyethylene, polypropylene and polyvinyl chloride (PVC) are the main example of thermosetting polymers. |
| A. | true |
| B. | false |
| Answer» C. | |
| 95. |
Which of the following types of molecular structure present in thermosetting polymers? |
| A. | linear polymers |
| B. | branched polymers |
| C. | cross-linked polymers |
| D. | network polymers |
| Answer» D. network polymers | |
| 96. |
Thermosetting plastics are generally used for making products of high strength and rigidness. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 97. |
Speed of production in transfer molding is higher than that of compression molding? |
| A. | true |
| B. | false |
| Answer» B. false | |
| 98. |
What is the minimum pressure required in a transfer molding process? |
| A. | 20 mpa |
| B. | 40 mpa |
| C. | 50 mpa |
| D. | 70 mpa |
| Answer» B. 40 mpa | |
| 99. |
What is the maximum curing time required in a compression molding process? |
| A. | 2 minutes |
| B. | 3 minutes |
| C. | 4 minutes |
| D. | 5 minutes |
| Answer» E. | |
| 100. |
In compression molding, the curing time does not depend on which of the following factors? |
| A. | material |
| B. | curing temperature |
| C. | geometry |
| D. | thickness |
| Answer» C. geometry | |