McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
| 1. |
The type of cam used for low and moderate speed engines is generally |
| A. | Involute |
| B. | Harmonic |
| C. | Flat |
| D. | Cylindrical |
| E. | Tangent |
| Answer» B. Harmonic | |
| 2. |
Which material is expected to be the hardest? |
| A. | Brass |
| B. | Copper-zinc |
| C. | Molybdenum |
| D. | Silver |
| E. | Aluminium |
| Answer» C. Molybdenum | |
| 3. |
If machine number is loaded in such a way that the three principla stresses at a point are 600 kg/cm2 compression. 800 kg/cm2 tension and zero. The maximum shear stress at the point will be |
| A. | 700 kg/cm2 |
| B. | 600 kg/cm2 |
| C. | 1000 kg/cm2 |
| D. | 800 kg/cm2 |
| E. | 200 kg/cm2 |
| Answer» A. 700 kg/cm2 | |
| 4. |
For minimum noise use which type of gears are used |
| A. | Bevel gears |
| B. | Hypoid gears |
| C. | Helical gears |
| D. | Cast steel |
| E. | Spur gears |
| Answer» C. Helical gears | |
| 5. |
In cross or regular lay ropes |
| A. | The direction of twist in wires in strands is opposite to the direction of twist of strands |
| B. | The direction of twist in wires in strands is the same as the direction of twist of strands |
| C. | Wires in two adjacent strands are twisted in opposite direction |
| D. | Wires are never twisted |
| E. | Only one wire is twisted and wrapped around |
| Answer» A. The direction of twist in wires in strands is opposite to the direction of twist of strands | |
| 6. |
In case of sunk key |
| A. | The key way is helical along the shaft |
| B. | The key way is cut in bub only |
| C. | The key way is cut in both shaft and hub |
| D. | The key way is cut in shaft only |
| E. | The key is in two parts |
| Answer» C. The key way is cut in both shaft and hub | |
| 7. |
The included angle of American National threads is |
| A. | 55? |
| B. | 50? |
| C. | 29? |
| D. | 47 |
| E. | 60? |
| Answer» E. 60? | |
| 8. |
Which of the following statement is false? |
| A. | Ball and roller bearings are anti-friction bearings |
| B. | The sleeve of a muff coupling is designed as a solid shaft |
| C. | In designing gear, the tooth is considered as a cantilever subjected to an end load |
| D. | Buttress threads are used to transmit power in one direction only |
| E. | Increasing the diameter of threaded portion |
| Answer» B. The sleeve of a muff coupling is designed as a solid shaft | |
| 9. |
Miter gears are |
| A. | Spur gears with same number of teeth |
| B. | Gears with different profiles |
| C. | Helical gears with same number of teeth |
| D. | Stepped spur gears |
| E. | Right angled bevel gears with same number of teeth |
| Answer» E. Right angled bevel gears with same number of teeth | |
| 10. |
Operation of helical gears is silent and quiet while the operation of the spur gears is noisy because |
| A. | helical gears have some helix angle but the spur gears are straight |
| B. | there is end thrust in helical gears |
| C. | in helical gears, contact begins at one end of the entering tooth and gradually extends along a diagonal line across the tooth face as the gears rotate |
| D. | none of the above |
| E. | Cast steel |
| Answer» C. in helical gears, contact begins at one end of the entering tooth and gradually extends along a diagonal line across the tooth face as the gears rotate | |
| 11. |
In the case of roller bearings the contacting areas between rollers and running tracks are |
| A. | Cast steel |
| B. | oblong |
| C. | parabolic |
| D. | elliptical |
| E. | circular |
| Answer» B. oblong | |
| 12. |
In door shutters, the type of the spring used is |
| A. | spiral spring |
| B. | helical torsion spring |
| C. | Cast steel |
| D. | close coiled helical spring |
| E. | conical helical spring |
| Answer» B. helical torsion spring | |
| 13. |
A foundation bolt with a circular end is secured to the floor by means of a steel cotter. If the pull on the bolt is 14000 kg, the diameter of the bolt should be |
| A. | Double shear |
| B. | 50 mm |
| C. | 10 mm |
| D. | 30 mm |
| E. | 20 mm |
| Answer» A. Double shear | |
| 14. |
The average values of modulus of rigidity for aluminium brass, copper and steel in descending order is |
| A. | Aluminium, nickel, brass, copper and steel |
| B. | Aluminium, copper, nickel, brass and steel |
| C. | Aluminium, copper, brass, nickel and steel |
| D. | Aluminium, brass, copper, nickel and steel |
| E. | Aluminium, brass, nickel, copper and steel |
| Answer» D. Aluminium, brass, copper, nickel and steel | |
| 15. |
In a ball bearing steel balls are made of |
| A. | Carbon steel |
| B. | Stainless steel |
| C. | Cast iron |
| D. | Carbon chrome steel |
| E. | Brass |
| Answer» D. Carbon chrome steel | |
| 16. |
In most machine members, the damping capacity of the material should be |
| A. | Anything |
| B. | Zero |
| C. | High |
| D. | Around zero |
| E. | Low |
| Answer» C. High | |
| 17. |
The loading on a pinion gear is usually |
| A. | Compression |
| B. | Tension |
| C. | Shear |
| D. | Cyclic loading |
| E. | None of the above |
| Answer» D. Cyclic loading | |
| 18. |
St, Venant's theory for failure of material is based on |
| A. | maximum shear stress |
| B. | maximum strain energy |
| C. | maximum tensile stress |
| D. | none of the above |
| E. | Increasing the diameter of threaded portion |
| Answer» B. maximum strain energy | |
| 19. |
The critical speed of a shaft is affected by |
| A. | Diameter of the disc |
| B. | Eccentricity |
| C. | Span of the shaft |
| D. | All of the above |
| E. | None of the above |
| Answer» D. All of the above | |
| 20. |
A thin cylinder contains fluid at a pressure of 30 kg kg/cm2, the internal diameter of the shell is 60 cm and the tensile stress in the material is to be limited to 900 kg/cm2. The shell must have a minimum wall thickness of |
| A. | 10 mm |
| B. | 9 mm |
| C. | 1 mm |
| D. | 27 mm |
| E. | 12 mm |
| Answer» A. 10 mm | |
| 21. |
Stub tooth |
| A. | Has a profile which is involutic at the base and cycloidal at the top |
| B. | Has a profile which is cycloidal at the base and involutic at the top |
| C. | Is provided on racks only |
| D. | Has a profile shorter than the standard tooth |
| E. | Has a profile longer than the standard tooth |
| Answer» D. Has a profile shorter than the standard tooth | |
| 22. |
Approximate horse power that can be transmitted by a shaft 60 mm diameter at 180 r.p.m. with permissible shear stress of 850 kg/cm2, would be |
| A. | 35-50 |
| B. | 85-95 |
| C. | 30-35 |
| D. | 50-65 |
| E. | 65-85 |
| Answer» B. 85-95 | |
| 23. |
The differential equation 10x + 9 x + 810x = 0 describes a one degree of freedom system. The natural frequency of the system is |
| A. | 90 cycles per second |
| B. | 9 cycles per second |
| C. | 10 cycles per second |
| D. | 90 sycles per second |
| E. | 9 radians per second |
| Answer» E. 9 radians per second | |
| 24. |
The concentric helical springs are wound in opposite direction |
| A. | to maintain identical shear stress in the two springs |
| B. | Increasing the diameter of threaded portion |
| C. | to maintain identical stiffness in both springs |
| D. | to avoid unequal deflection in the two springs |
| E. | to avoid binding of adjacent coils |
| Answer» E. to avoid binding of adjacent coils | |
| 25. |
The rivet diameter should be |
| A. | More than plate thickness |
| B. | Less than the plate thickness |
| C. | Equal to the plate thickness |
| D. | Equal to the strap thickness |
| E. | Half the plate thickness |
| Answer» A. More than plate thickness | |
| 26. |
In a horizontal flat belt drive for power transmission it is customary to use |
| A. | bottom side of the belt as slack side |
| B. | top side of the belt as slack side |
| C. | crossed-belting |
| D. | none of the above |
| E. | Cast steel |
| Answer» B. top side of the belt as slack side | |
| 27. |
Auto frettage is a |
| A. | extra cover provided on seamless pipes to increase their hoop stress |
| B. | a means of inducing favourable residual stresses in pressure vessels |
| C. | Increasing the diameter of threaded portion |
| D. | a heat treatment for pressure vessels subjected to low temperatures |
| E. | surface coating process |
| Answer» B. a means of inducing favourable residual stresses in pressure vessels | |
| 28. |
Bush bearings |
| A. | Phosphor bronze |
| B. | Aluminium bronze |
| C. | Mild steel |
| D. | White metal alloys |
| E. | None of the above |
| Answer» D. White metal alloys | |
| 29. |
In a standard coarse thread bolt the stress concentration is maximum at |
| A. | Top surface |
| B. | Pitch circle |
| C. | Root |
| D. | All over the surface |
| E. | Flank |
| Answer» C. Root | |
| 30. |
In case of worm and worm-wheel the maximum efficiency is obtained when |
| A. | Worm is driver |
| B. | Worm wheel is driver |
| C. | Either of the worm or worm wheel is a driver |
| D. | Depends on other factors |
| E. | None of the above |
| Answer» C. Either of the worm or worm wheel is a driver | |
| 31. |
When properly made, a butt weld has the strength equal to |
| A. | Double the tensile strength of plates |
| B. | Half the tensile strength of plates |
| C. | Half the compressive strength of plates |
| D. | The strength of the welded plates |
| E. | Double the compressive strength of plates |
| Answer» D. The strength of the welded plates | |
| 32. |
In case of steels, as the percentage of carbon content increases |
| A. | Percentage elongation decreases |
| B. | Weldability increases |
| C. | Tensile strength decreases |
| D. | Hardness decreases |
| E. | Tapered bearing |
| Answer» A. Percentage elongation decreases | |
| 33. |
At the first critical speed a shaft will |
| A. | Remain straight |
| B. | Bend to the simplest shape possible |
| C. | Bend to maximum permissible depth |
| D. | Bend to the convex form |
| E. | Vibrate producing audible sound |
| Answer» B. Bend to the simplest shape possible | |
| 34. |
In order to reverse the direction of rotation of a 3-phase induction motor |
| A. | Motor should eb replaced |
| B. | Power factor should be changed |
| C. | Supply voltage should be cut off in one phase |
| D. | Any two phases should be interchanged |
| E. | All the three phases should be interchanged |
| Answer» D. Any two phases should be interchanged | |
| 35. |
The basic hole is one which has |
| A. | Upper deviation as zero |
| B. | Lower deviation as zero |
| C. | Lower as well as upper deviation within narrow limits |
| D. | Lower as well as upper deviation are zero |
| E. | None of the above |
| Answer» B. Lower deviation as zero | |
| 36. |
In a Vee belt the angle between the sides is |
| A. | 30? |
| B. | 20? |
| C. | 60? |
| D. | 40? |
| E. | 10? |
| Answer» D. 40? | |
| 37. |
Gerber line for failure criteria is in the form of a |
| A. | parabola |
| B. | Increasing the diameter of threaded portion |
| C. | straight line with negative slope |
| D. | straight line with positive slope |
| E. | hyperbola |
| Answer» A. parabola | |
| 38. |
Which of the following formula for columns takes into account any initial crookedness of the column and imperfectness of axial loading? |
| A. | Secant formula |
| B. | Increasing the diameter of threaded portion |
| C. | Euler's formula |
| D. | Rankiness formula |
| E. | Perry Robertson formula |
| Answer» A. Secant formula | |
| 39. |
While designing a shaft pulley and key for a system |
| A. | Shaft is the weakest member |
| B. | Pulley is the weakest member |
| C. | Key is the weakest member |
| D. | All are designed for equal strength |
| E. | None of the above |
| Answer» C. Key is the weakest member | |
| 40. |
In case of biaxial stress system when a member is subjected to tensile stresses in two perpendicular directions the maximum shear stress in case of mild steel occurs on a plane inclined at |
| A. | 22 |
| B. | 75? |
| C. | 45? |
| D. | 67 |
| E. | 30? |
| Answer» C. 45? | |
| 41. |
For a bearing which of the following is maximum? |
| A. | Minimum life |
| B. | Average life |
| C. | Median life |
| D. | (A), (B) and (C) above are identical |
| E. | Increasing the diameter of threaded portion |
| Answer» C. Median life | |
| 42. |
The approximate value of allowable stress for carbon steel under static loading (in kg/cm2) is |
| A. | 500-1000 |
| B. | 10000-15000 |
| C. | 4000-7500 |
| D. | 20000-25000 |
| E. | 15000-20000 |
| Answer» C. 4000-7500 | |
| 43. |
Stub tooth is |
| A. | Longer than standard tooth depth |
| B. | Non-standard tooth |
| C. | Shorter than standard tooth depth |
| D. | Equivalent rack tooth |
| E. | Standard gear tooth |
| Answer» C. Shorter than standard tooth depth | |
| 44. |
Self-tapping screws are generally used in |
| A. | Shear metal work |
| B. | Machine tools |
| C. | Automobiles |
| D. | Aeroplanes |
| E. | None of the above |
| Answer» A. Shear metal work | |
| 45. |
Fatigue is mostly initiated at |
| A. | core |
| B. | centre |
| C. | Increasing the diameter of threaded portion |
| D. | surface |
| E. | core |
| Answer» D. surface | |
| 46. |
Which of the following joint is used for pipes carrying water under low pressures? |
| A. | Socket joint |
| B. | Increasing the diameter of threaded portion |
| C. | Expansion joint |
| D. | Adhesive joint |
| E. | Welded joint |
| Answer» A. Socket joint | |
| 47. |
In case of steels, as the percentage of carbon content increases |
| A. | Elongation increases |
| B. | Chrome steel |
| C. | Hardness decreases |
| D. | Tensile strength increases |
| E. | Weldability increases |
| Answer» D. Tensile strength increases | |
| 48. |
If screw threads are to be used in a situation involving high stresses in one direction only, the types of threads suitable for this would be |
| A. | BA |
| B. | BSW |
| C. | Buttress |
| D. | Acme |
| E. | Square |
| Answer» C. Buttress | |
| 49. |
A solderberg line for ductile material gives upper limit for |
| A. | Increasing the diameter of threaded portion |
| B. | alternating tensile stress |
| C. | alternating compressive stress |
| D. | any combination of mean and alternating stresses |
| E. | mean stress |
| Answer» D. any combination of mean and alternating stresses | |
| 50. |
If water in closed pipe freezes, the pipe will |
| A. | Rupture in a plane inclined at 45 degree to the longitudinal axis of the pipe |
| B. | Rupture along a line running longitudinally along the pipe |
| C. | Rupture along a plane perpendicular to the axis of pipe |
| D. | Rupture zig-zag along the length |
| E. | Rupture along weakest circumferential section |
| Answer» B. Rupture along a line running longitudinally along the pipe | |
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