MCQOPTIONS
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MCQOPTIONS
This section includes 382 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. |
Which of the following are the advantages of PBM? |
| A. | no chemical |
| B. | less harmful |
| C. | operates cleanly |
| D. | all of the mentioned |
| Answer» E. | |
| 52. |
What is the maximum thickness of the walls of tube machined using plasma arc? |
| A. | 10 mm |
| B. | 30 mm |
| C. | 50 mm |
| D. | 70 mm |
| Answer» D. 70 mm | |
| 53. |
What are the values of tolerances obtained by using PBM? |
| A. | ± 0.6 mm |
| B. | ± 1.6 mm |
| C. | ± 2.6 mm |
| D. | ± 3.6 mm |
| Answer» C. ± 2.6 mm | |
| 54. |
How much thickness of cracks may arise beyond HAZ due to rapid cooling? |
| A. | 1.6 mm |
| B. | 2.6 mm |
| C. | 3.6 mm |
| D. | 4.6 mm |
| Answer» B. 2.6 mm | |
| 55. |
The cut edge of the material tends to be than the base metal in PBM. |
| A. | smoother |
| B. | harder |
| C. | same as |
| D. | none of the mentioned |
| Answer» C. same as | |
| 56. |
What is the machining speed required for machining of 12mm thick plate with 220 kW energy? |
| A. | 1000 mm/min |
| B. | 1500 mm/min |
| C. | 2000 mm/min |
| D. | 2500mm/min |
| Answer» E. | |
| 57. |
What happens to the machining speed if the thickness of material is increased in PBM? |
| A. | decreases |
| B. | increases |
| C. | enhanced |
| D. | remains same |
| Answer» B. increases | |
| 58. |
A low power factors indicates energy required and removal rates. |
| A. | low, low |
| B. | low, high |
| C. | high, low |
| D. | high, high |
| Answer» C. high, low | |
| 59. |
Material removal rates depend on which of the following factors? |
| A. | work piece material |
| B. | type of cutting |
| C. | shielding gases |
| D. | all of the mentioned |
| Answer» E. | |
| 60. |
What is the maximum value of the thickness used in PBM process? |
| A. | 100 mm |
| B. | 200 mm |
| C. | 300 mm |
| D. | 400 mm |
| Answer» C. 300 mm | |
| 61. |
What is the value of the current used in PBM process? |
| A. | up to 200 a |
| B. | up to 400 a |
| C. | up to 600 a |
| D. | up to 800 a |
| Answer» D. up to 800 a | |
| 62. |
PBM is the only process which works faster in steel than steel. |
| A. | stainless, mild |
| B. | mild, stainless |
| C. | remains same all |
| D. | all of the mentioned |
| Answer» B. mild, stainless | |
| 63. |
What is to be done to the adherent material which are found at exit holes? |
| A. | shape them |
| B. | leave away |
| C. | remove them |
| D. | flatten them view answer |
| Answer» D. flatten them view answer | |
| 64. |
State whether the following statement regarding Laser beam machining is true or false. “In LBM, a blind hole of precise depth is easy to achieve.” |
| A. | true |
| B. | false |
| Answer» C. | |
| 65. |
Very holes with a aspect ratio can be produced using Laser beam machining. |
| A. | small, small |
| B. | small, large |
| C. | large, small |
| D. | large, large |
| Answer» C. large, small | |
| 66. |
Which of the following lasers is used for ceramic materials in LBM? |
| A. | pulsed co2 |
| B. | nd-yag |
| C. | pulsed co2 & nd-yag |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 67. |
Which of the following lasers is used for organics and non-metallic materials in LBM? |
| A. | co2 + gas assisted |
| B. | pulsed co2 |
| C. | nd-yag |
| D. | ruby |
| Answer» C. nd-yag | |
| 68. |
Which of the following lasers is used for slitting of thin plastic materials in LBM? |
| A. | co2 + gas assisted |
| B. | co2 only |
| C. | nd-yag |
| D. | ruby |
| Answer» C. nd-yag | |
| 69. |
Which of the following lasers is used for slitting of thin metallic materials in LBM? |
| A. | co2 + gas assisted |
| B. | co2 only |
| C. | nd-yag |
| D. | ruby |
| Answer» D. ruby | |
| 70. |
Which of the following lasers is used for cutting thick materials in LBM? |
| A. | co2 + gas assisted |
| B. | co2 only |
| C. | nd-yag |
| D. | ruby |
| Answer» B. co2 only | |
| 71. |
Which type of laser can be used for direct drilling or percussion? |
| A. | ruby laser |
| B. | nd-yag laser |
| C. | ruby & nd-yag laser |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 72. |
Which type of holes can be drilled using Nd-YAG laser? |
| A. | small holes |
| B. | large holes |
| C. | small & large holes |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 73. |
Which of the following materials can be easily separated by laser scribing? |
| A. | silicon |
| B. | glass |
| C. | ceramic |
| D. | all of the mentioned |
| Answer» E. | |
| 74. |
Material removal rates which are about mg/pulse produces which type of holes? |
| A. | shallow |
| B. | deep |
| C. | very deep |
| D. | all of the mentioned |
| Answer» B. deep | |
| 75. |
Lasers of which type are used for modification of electronic components? |
| A. | high power |
| B. | small spot size |
| C. | short pulse length |
| D. | all of the mentioned |
| Answer» E. | |
| 76. |
Work piece tilting depends on which of the following factors? |
| A. | incident power |
| B. | beam speed |
| C. | groove direction |
| D. | all of the mentioned |
| Answer» E. | |
| 77. |
Which of the following are the other applications of LBM? |
| A. | dressing of grinding wheels |
| B. | scribing |
| C. | micromachining |
| D. | all of the mentioned |
| Answer» E. | |
| 78. |
How the grooves in grinding wheels are produced using laser? |
| A. | evaporation |
| B. | damage of composite |
| C. | evaporation & damage of composite |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 79. |
State whether the following statement is true regarding the texturing in LBT. “In LBT, hardness of the material is a limitation to the process.” |
| A. | true |
| B. | false |
| Answer» C. | |
| 80. |
The roll is and the laser beam is moved along the roll. |
| A. | stationary, axially |
| B. | stationary, perpendicularly |
| C. | rotated, axially |
| D. | rotated, perpendicularly |
| Answer» D. rotated, perpendicularly | |
| 81. |
Where are the textured surfaces used that are obtained in LBT? |
| A. | mould makings |
| B. | bearings |
| C. | printer roll manufacturing |
| D. | all of the mentioned |
| Answer» E. | |
| 82. |
Depth and the crater size depends on which of them below? |
| A. | energy of beam |
| B. | dwell time of beam |
| C. | energy & dwell time of beam |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 83. |
What is the full form of LBT in the processes of LBM? |
| A. | laser beam tempering |
| B. | laser beam templating |
| C. | laser beam texturing |
| D. | laser beam tinning |
| Answer» D. laser beam tinning | |
| 84. |
What happens to the cutting speed with an increase in the work piece? |
| A. | increases |
| B. | decreases |
| C. | enhances |
| D. | remains same |
| Answer» C. enhances | |
| 85. |
Which gas jet assisted process is suitable for most of the metals? |
| A. | oxygen gas |
| B. | nitrogen gas |
| C. | helium gas |
| D. | all of the mentioned |
| Answer» B. nitrogen gas | |
| 86. |
What range of powers are used for cutting through steel? |
| A. | 1 to 20 w |
| B. | 20 to 100 w c) 200 to 1000 w |
| C. | 1 to 20 kw |
| Answer» D. | |
| 87. |
Which of the following properties of material affect the quality of holes obtained? |
| A. | reflectivity |
| B. | absorption coefficient |
| C. | thermal conductivity |
| D. | all of the mentioned |
| Answer» E. | |
| 88. |
Selection of assist gas depends on which of the following properties of work piece? |
| A. | material |
| B. | thickness |
| C. | material & thickness |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 89. |
Which of the following are the functions of assist gases? |
| A. | removal of molten material |
| B. | shield the lenses |
| C. | better efficiency |
| D. | all of the mentioned |
| Answer» E. | |
| 90. |
pulse energy and pulse duration are suitable for drilling. |
| A. | low, short |
| B. | low, long |
| C. | high, short |
| D. | high, long |
| Answer» D. high, long | |
| 91. |
Drilling of holes with larger pulse duration causes which effect to the holes produced? |
| A. | enlarge holes |
| B. | reduce hole size |
| C. | decrease the depth |
| D. | all of the mentioned |
| Answer» B. reduce hole size | |
| 92. |
Peak power should be increased in Laser drilling process by pulse energy. |
| A. | increasing |
| B. | decreasing |
| C. | reducing |
| D. | constant |
| Answer» B. decreasing | |
| 93. |
What is the depth-to-diameter ratio obtained in drilling process using Laser beam machining? |
| A. | 10:1 |
| B. | 20:1 |
| C. | 50:1 |
| D. | 80:1 |
| Answer» D. 80:1 | |
| 94. |
State whether the following statement is true or false regarding the drilling using LBM. “Compared to LBM, conventional machining is more accurate and efficient.” |
| A. | true |
| B. | false |
| Answer» C. | |
| 95. |
How much amount of incident radiation is reflected at lower power densities? |
| A. | 10 percent |
| B. | 20 percent |
| C. | 50 percent |
| D. | 90 percent |
| Answer» E. | |
| 96. |
How are minimum energies required for plastics when compared to that required for metals? |
| A. | lower than |
| B. | higher than |
| C. | same as |
| D. | none of the mentioned |
| Answer» B. higher than | |
| 97. |
Machining of LBM takes place when power density is than what is lost by conduction and radiation. |
| A. | greater |
| B. | smaller |
| C. | lower |
| D. | same as |
| Answer» B. smaller | |
| 98. |
What is the wavelength value of CO2 laser used in Laser beam machining? |
| A. | 0.16 μm |
| B. | 1.6 μm |
| C. | 10.6 μm |
| D. | 106 μm |
| Answer» D. 106 μm | |
| 99. |
What is the wavelength value of neutral gas laser used in LBM? |
| A. | 633 nm |
| B. | 694 nm |
| C. | 856 nm |
| D. | 1064 nm |
| Answer» B. 694 nm | |
| 100. |
For manufacturing of complex shapes, soft electrode wires are used. |
| A. | true |
| B. | false |
| Answer» B. false | |