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This set of Machine Design Multiple Choice Questions & Answers (MCQs) focuses on Machine Design Set 15

Q1 | For a parallel load on a fillet weld of equal leg the plane of maximum shear occurs
  • Almost vertically
  • Almost horizontallly
  • At 45? to the horizontal
  • At 30? to the vertical
  • At 30? to the horizontal
Q2 | Which of the following types of gears are free from interference?
  • Cycloidal
  • Epicycloidal
  • Involute
  • Stub
  • Hypocycloidal
Q3 | A section is subjected to reversal of stresses. Choice exists for selecting any of the following section. Which one should be selected?
  • T-section
  • Unequal angle iron
  • Channel section
  • Hollow pipe
  • Equal angle iron
Q4 | For the plastic analysis, the criterion for the analysis of a structure is based upon
  • yield load
  • Increasing the diameter of threaded portion
  • ultimate load
  • working load
  • breaking load
Q5 | Two plates are joined by a parallel fillet welds. The plates are subjected to a tensile load of 35000 kg. If the allowable shear stress for the weld material be 800 kg the minimum length of 15 mm weld required to resist this load would be
  • 41 cm
  • 20.5 cm
  • 10 cm
  • 61.5 cm
  • 82 cm
Q6 | A spherical metal vessel 120 cm diameter is subjected to an internal pressure of 15 kg/sq cm. If the permissible stress is 625 kg/sq cm and the efficiency of the riveted joints is 75%, the required thickness of the plate would be
  • 10 mm
  • 2 mm
  • 5 mm
  • 1 mm
  • 8 mm
Q7 | Belt slip may occur due to
  • None of above
  • Any of above
  • Loose belt
  • Heavy load
  • Driving pulley too small
Q8 | The plastic hinge in a section is caused when
  • all the fibres at a section reach the yield state
  • the material at a section reaches plastic state
  • the extreme fibres at a section reach the yield state
  • none of the above
  • Increasing the diameter of threaded portion
Q9 | The thickness of a gear tooth is measured
  • Along the pitch circle
  • Along the root circle
  • Along the outer circle
  • Average of the profile
  • None of the above
Q10 | The life of a ball bearing is usually given in
  • hours of service
  • total rpm
  • either of (A) or (B) above
  • none of the above
  • Increasing the diameter of threaded portion
Q11 | In bolts the stress in the unthreaded area (the shank) is
  • lower
  • lower higher
  • higher
  • Increasing the diameter of threaded portion
  • higher or lower
Q12 | Life of a rolling bearing as listed in a catalogue is usually
  • minimum expected life
  • maximum expected life
  • mean life
  • none of the above
  • Increasing the diameter of threaded portion
Q13 | For the same power transmission, V-belts are
  • wider, thinner
  • thinner, wider
  • Increasing the diameter of threaded portion
  • narrow, thicker
  • thicker, narrow
Q14 | Which of the following alloying metal for steels acts as a deoxidizing and desulphurising agent?
  • Nickel
  • Increasing the diameter of threaded portion
  • Chromium
  • Tungsten
  • Manganese
Q15 | The coefficient of friction in a rolling bearing is of the order of
  • 0.01
  • 0.1
  • 0.2
  • 0.05
  • 0.001
Q16 | According to Indian Boiler Regulations the essential requirement of any safety valve is that
  • It should be costly
  • It should have good appearance
  • Its area should be sufficient to discharge the steam as quickly as it is generated with rise in pressure not more than 10% of the safety valve blow off pressure
  • It should be located outside the boiler room
  • It should be visible to boiler operator from all positions in the boiler room
Q17 | Which of the following material is not suitable for impact loads?
  • Cast iron
  • Chrome steel
  • Mild steel
  • High carbon steel
  • Manganese steel
Q18 | The fatigue limit of a material
  • Is greatly decreased by poor surface conditions
  • Is improved if there is rough surface
  • Is independent of surface conditions
  • Surface defects which extend upto core have no influence of fatigue limits
  • None of the above
Q19 | The material of a flt spiral spring is in a state of
  • pure torsion
  • pure bending
  • torsion and bending
  • none of the above
  • Cast steel
Q20 | Safety valve used on locomotive boilers is generally of
  • Spring balanced type
  • Lever load type
  • Spring type
  • Indirect dead weight type
  • Dead weight type
Q21 | The limit design of steel structures makes use of
  • elastic and plastic analysis of structures
  • ultimate analysis
  • Increasing the diameter of threaded portion
  • plastic analysis of structures
  • elastic analysis of structures
Q22 | Gas lubricated bearings are used for
  • very high rpm and high load applications
  • very low rpm and high load applications
  • very low rpm and low load applications
  • Increasing the diameter of threaded portion
  • very high rpm and low load applications
Q23 | In a ball bearing a ball is subjected to
  • Compressive stress
  • Tensile stress
  • Shear stress
  • Cyclic stress or fatigue
  • None of the above
Q24 | Backlash is
  • Sum of the clearance of two gears
  • Mutual play between two gears
  • The amount by which the width of a tooth space exceeds the thickness of the engaging tooth on pitch circle
  • Any of the above
  • None of the above
Q25 | A cantilever beam of square section is subjected to a load W at the free end. If the length of the beam is increased and load reduced to half the deflection at the free end as compared to original deflection would be
  • 4 times
  • 16 times
  • 1/2 times
  • 2 times
  • 8 times