81. Which of the following ceramic materials are used for piezoelectric applications?
(a) Alumina and zirconium oxides
(b) Boron titanate and silicon carbide
(c) Barium titanate and lead-zirconate-titanate
(d) Porcelain and fused silica glass
Answer: (a)
82. Statement (I): Both oblique shock and normal shock can be viewed as two different regions of a flow over a plate with a deflection section.
Statement (II): Variation of the deflection angle from a zero to a positive value results in oblique shock. Further changing the deflection angle to a negative value results in expansion waves.
(a) Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I)
(b) Both Statement (I) and Statement (II) are individually true but Statement (II) is NOT the correct explanation of Statement (I)
(c) Statement (I) is true but Statement (II) is false
(d) Statement (I) is false but Statement (II) is true
Answer: (a)
83. In the metal forming processes, the stresses encountered are, less than the:
1. Yield strength of the material
2. Fracture strength of the material and greater than yield strength
Which of the above statements is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
Answer: (b)
84. Consider the following objectives of sintering in powder metallurgy:
1. To achieve good bonding of powder particles
2. To produce a dense and compact structure
3. To achieve high strength
4. To produce parts free of any oxide
Which of the above objectives are correct?
(a) 1, 2 and 3 only
(b) 1, 2 and 4 only
(c) 3 and 4 only
(d) 1, 2, 3 and 4
Answer: (d)
85. In any casting process, shrinkage allowance on the pattern is provided in order to compensate for shrinkage when
(a) The temperature of the liquid metal drops from the pouring to its freezing temperature
(b) The metal changes from the liquid to the solid state at its freezing temperature
(c) The temperature of solid phase drops from its freezing temperature to room temperature
(d) The temperature of metal drops from its pouring temperature to room temperature
Answer: (c)
86. Investment casting is used for
(a) Mass production
(b) Shapes that are made with difficulty using complex patterns in sand casting
(c) Stainless steel parts
(d) Shapes which are complex, intricate and cannot be cast by any other method
Answer: (d)
87. Statement (I): The efficiency of steam turbine considerably reduces if throttle governing is carried out at lower loads.
Statement (II): Nozzle control can only be applied to the first stage of turbine.
(a) Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I)
(b)Both Statement (I) and Statement (II) are individually true but Statement (II) is NOT the correct explanation of Statement (I)
(c) Statement (I) is true but Statement (II) is false
(d)Statement (I) is false but Statement (II) is true
Answer: (a)
88. Consider the following statements with regard to the feeding system for a casting:
1. The feeder should be thermally adequate
2. The feeder should be volumetrically adequate
3. The feeder should have adequate feeding range
Which of the above statements are correct?
(a) 1 and 2 only
(b) 1 and 3 only
(c) 2 and 3 only
(d) 1, 2 and 3
Answer: (d)
89. Consider the following statements:
1. Depth of penetration of a weld depends on the electron speed which is dependent on the accelerating voltage
2. The output of the Ruby Laser is normally in ‘pulses’
3. Joints with curvatures cannot be welded conveniently
Which of the above statements are relevant to Electron Beam Welding process?
(a) 1 and 2 only
(b) 1 and 3 only
(c) 2 and 3 only
(d) 1, 2 and 3
Answer: (b)
90. The difference between (i) a horizontal borer and (ii) a lathe is
(a) In (i) the spindle is horizontal; in (ii) it is vertical
(b) In (i) the tool rotates; in (ii) the object rotates
(c) In (i) the object rotates; in (ii) tool rotates
(d) (i) produces a plain surface; (ii) produces a cylindrical surface
Answer: (b)
Solved Question Paper for Foreman (Mechanical) in Ministry of Defence, Junior Scientific Officer (Mechanical) in Ministry of Defence, Assistant Executive Engineer (Mechanical), Additional Assistant Director (Safety) (Mechanical), Senior Scientific Assistant (Mechanical), Ministry of Defence & Junior Works Manager (Mechanical), Ministry of Defence conducted by UPSC
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UPSC Mechanical
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