MCQOPTIONS
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MCQOPTIONS
This section includes 112 Mcqs, each offering curated multiple-choice questions to sharpen your Machine Tools knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
In solidification of metal during casting, compensation for solid contraction is |
| A. | Provided by the oversize pattern |
| B. | Achieved by properly placed risers |
| C. | Obtained by promoting direction solidification |
| D. | Made by providing chills |
| Answer» B. Achieved by properly placed risers | |
| 52. |
In a casting process the height of the molten metal from the ingate to the pattern is 0.5 m, then the velocity of flow of the molten metal through the in gate is __________ (Assume acceleration due to gravity as 10 m / s2 ) |
| A. | 10 m / s |
| B. | \( { \sqrt{10}}~m~/~s\) |
| C. | 0.5 m / s |
| D. | √5 m / s |
| Answer» C. 0.5 m / s | |
| 53. |
Chaplets are made of |
| A. | graphite |
| B. | plastic |
| C. | same metal as the cast metal |
| D. | none of the above |
| Answer» D. none of the above | |
| 54. |
Assertion (A): Aluminium alloys are cast in a hot chamber die casting machine.Reason (R): Aluminium alloys require high melting when compared to zinc alloys. |
| A. | Both A and R individually true and R is the correct explanation of A. |
| B. | Both A and R individually true and R is not the correct explanation of A. |
| C. | A is true but R is false |
| D. | A is false but R is true |
| Answer» E. | |
| 55. |
Match the following sand mold casting defects with their respective causes.DefectCauseP. Blow hole1. Poor collapsibilityQ. Misrun2. Mold erosionR. Hot tearing3. Poor permeabilityS. Wash4. Insufficient fluidity |
| A. | P-4, Q-3, R-1, S-2 |
| B. | P-3, Q-4, R-2, S-1 |
| C. | P-2, Q-4, R-1, S-3 |
| D. | P-3, Q-4, R-1, S-2 |
| Answer» E. | |
| 56. |
A sand casting mould assembly is show in the given figure. The element marked A and B are |
| A. | Sprue and riser |
| B. | Ingate and riser |
| C. | Drag and runner |
| D. | Riser and runner |
| Answer» E. | |
| 57. |
Chills are |
| A. | Metallic objects to provide very low heat extraction capability of sand mould |
| B. | Metallic objects to provide strength of sand mould |
| C. | Metallic objects to provide very high heat extraction capability of sand mould |
| D. | Mixed in sand to enhance its collapsibility |
| Answer» D. Mixed in sand to enhance its collapsibility | |
| 58. |
Match List-I with List-II and select the correct answer using the given listsList IList IIA. Hollow statuea. CentrifugalB. Denturesb. Investment castingC. Aluminium alloy pistonsc. Slush castingD. Rocker armsd. Shell moulding e. Gravity die casting |
| A. | A - c, B - b, C - d, D - e |
| B. | A - a, B - c, C- d, D - e |
| C. | A - a, B - b, C - c, D - d |
| D. | A - c, B - b, C - e, D - d |
| Answer» E. | |
| 59. |
In sand moulding, the bottom flask is called |
| A. | Cope |
| B. | Drag |
| C. | Fillet |
| D. | Riddle |
| Answer» C. Fillet | |
| 60. |
Metal supports used to keep the cores from shifting are called |
| A. | core prints |
| B. | chaplets |
| C. | chills |
| D. | sprue |
| Answer» C. chills | |
| 61. |
Chills are used in casting moulds to |
| A. | Achieve directional solidification |
| B. | Reduce possibility of blow holes |
| C. | Reduce the freezing time |
| D. | Increase the smoothness of cost surface |
| Answer» B. Reduce possibility of blow holes | |
| 62. |
Blow molding process to produce object such as bottles & floatable objects can be applied to only |
| A. | Thermo setting plastics |
| B. | Thermo plastics |
| C. | Lamented plastics |
| D. | Reinforced plastics |
| Answer» C. Lamented plastics | |
| 63. |
Colour code for part to be machined for wooden patterns is represented by following colour : |
| A. | Red or orange |
| B. | Yellow |
| C. | Black on core prints |
| D. | Green |
| Answer» C. Black on core prints | |
| 64. |
A schematic diagram of the poring basin and the sprue of a gating system is shown in the figure. The depth of molten metal in the pouring basin is 100 mm and the height of the sprue is 1,500 mm.Considering the cross-section of the sprue is circular, the ratio d1 : d2 to avoid aspiration is |
| A. | 3 : 2 |
| B. | 5 : 6 |
| C. | 15 : 16 |
| D. | 1 : 2 |
| Answer» E. | |
| 65. |
During solidification of pure molten metal, the grains in the casting near the mould wall are |
| A. | coarse and randomly oriented |
| B. | fine and randomly oriented |
| C. | fine and ordered |
| D. | coarse and ordered |
| Answer» C. fine and ordered | |
| 66. |
In a non-pressurized gating system, a metal alloy is poured at a volumetric flow rate of 8 × 10-4 m3/s through a sprue with a base cross-sectional area of 400 mm2. Neglecting any frictional losses, what is the height of sprue in mm? (assume g = 10 m2/s) |
| A. | 175 |
| B. | 275 |
| C. | 200 |
| D. | 225 |
| Answer» D. 225 | |
| 67. |
A cube shaped casting solidifies in 5 minutes. The solidification time in minutes for a cube of the same material, which is 8 times heavier than the original casting will be |
| A. | 10 |
| B. | 20 |
| C. | 24 |
| D. | 40 |
| Answer» C. 24 | |
| 68. |
_______ are casting defects by improper shrinkage / hindered contraction. |
| A. | Hot tears |
| B. | Swell |
| C. | Shifts |
| D. | Fins |
| Answer» B. Swell | |
| 69. |
Graphite moulds are generally used for continuous casting method because |
| A. | the metals wet the mould slightly |
| B. | only a small film of lubricating oil is required |
| C. | they are self-lubricating |
| D. | they are comparatively cheaper |
| Answer» D. they are comparatively cheaper | |
| 70. |
In a sand casting operation, the total liquid head is maintained constant such that it is equal to the mould height. The time taken to fill the mould with a top gate is tA. If the same mould is filled with a bottom gate, then the time taken is tB. Ignore the time required to fill the runner and frictional effects. Assume atmospheric pressure at the top molten metal surfaces. The relation between tA and tB is: |
| A. | \({t_B} = \sqrt 2 {t_A}\) |
| B. | \({t_B} = 2{t_A}\) |
| C. | \({t_B} = \frac{{{t_A}}}{{\sqrt 2 }}\) |
| D. | \({t_B} = 2\sqrt 2 {t_A}\) |
| Answer» C. \({t_B} = \frac{{{t_A}}}{{\sqrt 2 }}\) | |
| 71. |
Casting process is preferred for parts having ______. |
| A. | A few details |
| B. | Many details |
| C. | No details |
| D. | Non-symmetrical shape |
| Answer» C. No details | |
| 72. |
In which of the following processes, metal moulds are used? |
| A. | Sand casting |
| B. | Investment casting |
| C. | Shell moulding |
| D. | Die casting |
| Answer» E. | |
| 73. |
In centrifugal casting, the cores are generally made of |
| A. | Wax |
| B. | Plastic |
| C. | Plaster of Paris |
| D. | Cores are not used |
| Answer» E. | |
| 74. |
Investment casting uses pattern made of |
| A. | Metal |
| B. | Wood |
| C. | Plastic |
| D. | Wax |
| Answer» E. | |
| 75. |
A casting of size 100 × 100 × 100 mm3 solidifies in 20 minutes. Find out the solidification time for casting of size 100 × 100 × 50 mm3 under same condition. |
| A. | 16.3 minutes |
| B. | 14.3 minutes |
| C. | 12.3 minutes |
| D. | 11.3 minutes |
| Answer» E. | |
| 76. |
Chaplets are used in mould for |
| A. | Enhancing the rate of solidification |
| B. | Providing additional metal to the casting as it shrinks |
| C. | Carrying off gates produced during casting |
| D. | Providing support to the core |
| Answer» E. | |
| 77. |
A sprue hole is _____. |
| A. | A casting defect |
| B. | A hold made for riveting |
| C. | A blind hole in jigs |
| D. | An opening in mould for pouring molten metal |
| Answer» E. | |
| 78. |
Consider the following statements.(1) Hot chamber machine is used for casting zinc, tin and other low melting alloys(2) Cold chamber machine is used for die casting of ferrous alloys(3) Rapid cooling rate in die casting produces high strength and quality in many alloysWhich of these statements are correct? |
| A. | 1,2 and 3 |
| B. | 1 and 2 only |
| C. | 2 and 3 only |
| D. | 1 and 3 only |
| Answer» E. | |
| 79. |
Centrifugally cast products have |
| A. | larger grain structure with high porosity |
| B. | fine grain structure with high density |
| C. | fine grain structure with low density |
| D. | segregation of slug towards the outer skin of the casting |
| Answer» C. fine grain structure with low density | |
| 80. |
In a radiographic test, type of defect not detectable by X-Ray is |
| A. | Delamination in cladded sheet |
| B. | Porosity in castings |
| C. | Tungsten inclusion in TIG weld |
| D. | Under cut in metal arc welding |
| Answer» E. | |
| 81. |
A spherical drop of molten iron of radius 2 mm solidifies in 10 s. A similar drop of radius 4 mm will solidify in: |
| A. | 10 s |
| B. | 30 s |
| C. | 20 s |
| D. | 40 s |
| Answer» E. | |
| 82. |
In carbon dioxide moulding process, the binder used is: |
| A. | Sodium bentonite |
| B. | Calcium bentonite |
| C. | Sodium silicate |
| D. | Phenol formaldehyde |
| Answer» D. Phenol formaldehyde | |
| 83. |
For Gating system of casting, choke area (A) may be written as [where, m = mass of casting, ρ = density of molten metal, H = effective metal height, C = efficiency factor, t = pouring time]: |
| A. | \(A = \frac{m}{{\rho tC\sqrt {2gH} }}\) |
| B. | \(A = \frac{{tm}}{{\rho C\sqrt {2gH} }}\) |
| C. | \(A = \frac{{m\sqrt {2gH} }}{{\rho tC}}\) |
| D. | \(A = \frac{{\rho m}}{{tC\sqrt {2gH} }}\) |
| Answer» B. \(A = \frac{{tm}}{{\rho C\sqrt {2gH} }}\) | |
| 84. |
Cast iron pipes are manufactured by: |
| A. | Centrifugal casting method |
| B. | Die casting method |
| C. | Sand casting method |
| D. | Lost wax method |
| Answer» B. Die casting method | |
| 85. |
Moulds made of metals that maintain their strength at high temperature are: |
| A. | Permanent moulds |
| B. | Composite Moulds |
| C. | Expendable moulds |
| D. | Green sand mould |
| Answer» B. Composite Moulds | |
| 86. |
A cube shaped casting solidifies In 10 minutes. Time taken by the same material cube 27 times heavier than the original one in minutes will be: |
| A. | 90 |
| B. | 75 |
| C. | 10 |
| D. | 60 |
| Answer» B. 75 | |
| 87. |
In a gating system design, a down sprue of 180 mm length has a diameter of 20 mm at its top end. The liquid metal in the pouring cup is maintained up to 60 mm height. The diameter (in mm) of the down sprue at its lower end to avoid aspiration will be: |
| A. | 11.11 |
| B. | 14.14 |
| C. | 25 |
| D. | 17.32 |
| Answer» C. 25 | |
| 88. |
Gate is provided in moulds to |
| A. | Feed the casting at constant rate |
| B. | Give passage to gases |
| C. | Compensate for shrinkage |
| D. | Avoid cavities |
| Answer» B. Give passage to gases | |
| 89. |
For the sprue shown below what should be the area at point 3 in order to avoid aspiration effect? Given area at point 2 = 125 cm2. |
| A. | 79.05 cm2 |
| B. | 105.84 cm2 |
| C. | 66.81 cm2 |
| D. | 96.82 cm2 |
| Answer» D. 96.82 cm2 | |
| 90. |
Draft on pattern for casting is provided for |
| A. | Shrinkage allowance |
| B. | Identification |
| C. | Taper to facilitate removal from mould |
| D. | Machining allowance |
| Answer» D. Machining allowance | |
| 91. |
In small, castings, which of the following allowances can be ignored. |
| A. | Shrinkage Allowance |
| B. | Rapping Allowance |
| C. | Draft Allowance |
| D. | Machining Allowance |
| Answer» C. Draft Allowance | |
| 92. |
A mould has a down sprue whose length is 20 cm and the cross-sectional area at the base of the down sprue is 1 cm2. The down sprue feeds a horizontal runner leading into the mould cavity of volume 2000 cc. The time required to fill the mould cavity will be |
| A. | 10.1 s |
| B. | 4.05 s |
| C. | 5.05 s |
| D. | 7.25 s |
| Answer» B. 4.05 s | |
| 93. |
In a sand casting process, a sprue of height 200 mm and 10 mm base diameter leads to a runner which fills a cubical mould cavity of 200 mm side. Time required to fill the cavity will be: [discharge coefficient = 1, g = 10 m/s2] |
| A. | 560/11 sec |
| B. | 460/11 sec |
| C. | 360/11 sec |
| D. | 260/11 sec |
| Answer» B. 460/11 sec | |
| 94. |
Core prints are used for |
| A. | Strengthen core |
| B. | Form seat to support and hold the core in-place |
| C. | Fabricate core |
| D. | None of the above |
| Answer» C. Fabricate core | |
| 95. |
A cylindrical blind riser with diameter d and height h, is placed on the top of the mould cavity of a closed type sand mould as shown in the figure. If the riser is of constant volume, then the rate of solidification in the riser is the least when the ratio h : d is |
| A. | 1 : 2 |
| B. | 2 : 1 |
| C. | 1 : 4 |
| D. | 4 : 1 |
| Answer» B. 2 : 1 | |
| 96. |
Consider the following statements for an induction furnace:1. High-frequency current is generally used for the furnace working.2. There is less loss of alloying elements due to oxidation.3. Pronounced stirring action of molten metal occurs inside the furnace.4. Slag cover is essential for the efficient working of the furnace.Which of the above statements are correct? |
| A. | 1, 3 and 4 only |
| B. | 2, 3 and 4 only |
| C. | 1, 2 and 3 only |
| D. | 1, 2, 3 and 4 |
| Answer» E. | |
| 97. |
Consider the following statements:In shell moulding1) a single parting plane should be provided for mould2) detachable pattern parts and cores could be included3) minimum rounding radii of 2.5 mm to 3 mm should be used4) draft angles of not less than 1° should be usedWhich of the above statements are correct? |
| A. | 1, 3 and 4 only |
| B. | 1, 2 and 3 only |
| C. | 2, 3 and 4 only |
| D. | 1, 2, 3 and 4 |
| Answer» B. 1, 2 and 3 only | |
| 98. |
A spherical drop of molten metal of radius 5 mm was found to solidify in 12 s. In how much time will a similar drop of radius 10 mm solidify? |
| A. | 6 sec |
| B. | 12 sec |
| C. | 24 sec |
| D. | 48 sec |
| Answer» E. | |
| 99. |
Petrol engine carburetors are manufactured by ________ |
| A. | Shell casting |
| B. | Centrifugal casting |
| C. | Die casting |
| D. | Sand casting |
| Answer» D. Sand casting | |
| 100. |
Pattern material used for precision casting is: |
| A. | wooden pattern |
| B. | wax pattern |
| C. | no pattern |
| D. | metal pattern |
| Answer» C. no pattern | |