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This set of Machine Design Multiple Choice Questions & Answers (MCQs) focuses on Machine Design Set 3
Q1 | A self-socking screw is one which
- Has locking arrangement
- Has a hole drilled through for inserting locking pin
- Has coefficient of friction equal to or greater than the tangent of the load angle
- Has fine pitch screw threads
- None of the above
Q2 | A taper bearing has
- Tapered roller
- Tapered inner race
- Tapered shaft
- Tapered cage
- Tapered outer race
Q3 | Resistance to fatigue of a material is measured by
- Modulus of rigidity
- Electricity parameters
- Endurance limit
- Elastic limit
- Youngs modulus
Q4 | Wing screws are used where
- tight grip is essential
- frequently manual locking and unlocking is necessary
- stress reversal is severe
- high torque is needed for tightening
- Increasing the diameter of threaded portion
Q5 | Maximum gear ratio can be expected in case of
- Spur gears
- Worm and worm wheel
- Helical gears
- Straight bevel gears
- Double helical gears
Q6 | The edges of boiler plates for fullering and caulking are bevelled at an angle of
- 60?
- 45?
- 70?
- 30?
- 80?
Q7 | Spring index is
- Load carrying capacity of a spring
- The ratio of coil diameter to wire diameter
- The ratio of coil diameter to wire diameter
- An indication of the equality of springs
- The ratio of free length to that under design load
Q8 | Regenerative braking is used on
- Earth moving machines
- Heavy duty trucks
- Electric locomotives
- Diesel locomotives
- Steam locomotives
Q9 | The plastic section modulus is
- the ratio of plastic moment capacity of a section to the yield moment
- Increasing the diameter of threaded portion
- the ratio of moment of inertia to radius of gyration
- the ratio of plastic moment capacity to the field stress
- area multiplied by the radius of gyration
Q10 | All of the following statements are false except
- The pitch of a sinle threaded screw is equal to the lead
- In a flange coupling, the bolts are subjected to compressive stress
- Oldham coupling is used for connecting piston rod of a steam engine to the cross head
- The resilience of a bolt may be increased by decreasing its shank diameter
- Increasing the diameter of threaded portion
Q11 | Neglecting bending, for a parallel load on a fillet weld of equal legs the plane of maximum shear occurs at
- 45?
- 15?
- 60?
- 30?
- 22
Q12 | In watches and gramophones, which spring is most commonly used
- Flat spiral spring
- torsion helical spring
- conical helical spring
- none of the above
- Cast steel
Q13 | The edge of the plates for boilers and tanks are usually bevelled at an angle of 80?
- To reduce stress concentration
- For safety
- To facilitate joining
- For fullering and caulking
- None of the above
Q14 | The basic design stress adopted for the design of light gauge steel members is
- the stress at limit of proportionality
- the yield stress divided by 1.85
- the yied stress
- the permissible stress
- Increasing the diameter of threaded portion
Q15 | Lewis equation in ears is used to evaluate
- Tensile stress in bending
- Compressive stress in bending
- Creep stress
- Endurance limit
- Shear stress on flank
Q16 | If a machine member is loaded in such a way that the three principal stresses at a point are 600 kg/cm2 tension, 800 kg/cm2 compression and zero. The maximum shear stress at the point will be
- 400 kg/cm2
- 800 kg/cm2
- 600 kg/cm2
- 1000 kg/cm2
- 200 kg/cm2
Q17 | In V-belt drive the belt touches
- At bottom
- At sides only
- Both at bottom as well as sides
- Anywhere
- None of the above
Q18 | Ball bearing type screws
- Sliding friction is replaced by rolling friction
- There is a ball bearing provided on the screwed shafts
- Are self-locking
- Friction is more
- Have load bearing capacity for more than vee threads
Q19 | Stub teeth are provided on gears
- For high velocity ratios
- Low noise
- Large power transmission
- Improved capability to withstand shock and vibrations
- All of the above
Q20 | Which of the following is not the result of cold work?
- Increased tensile strength
- Increasing the diameter of threaded portion
- Reduced ductility
- Reduced shock resistance
- Reduced hardness
Q21 | In a stone jaw crusher the main crank bearings are
- Taper roller bearings
- Roller bearings
- Ball bearings
- Double row ball bearings
- Self-aligning ball bearings
Q22 | The piston of a internal combustion engine is subjected to
- fully reversed stresses
- repeated stresses
- Increasing the diameter of threaded portion
- partly repeated stresses
- partly reversed stresses
Q23 | Spring stiffness is
- Load carrying capacity of spring
- Load per unit area of base
- Load/cross-sectional area of spring
- Load/unit deflection
- None of the above
Q24 | In a central heating system, the seamless copper tubing used has an inside diameter of 20 mm and a wall thickness of 0.6 mm. For a maximum pressure of 1750 Kpa, when allowable stress is 225 Mpa, the safety factor will be
- 7.7
- 9.9
- 3.3
- 5.5
- Increasing the diameter of threaded portion
Q25 | While designing for screw threads care should be taken to provide adequate length of engagement for the screw and nut threads so as to prevent failure of threads in
- Tension
- Compression
- Torque
- Shear
- None of the above