MECHANICAL ENGINEERING- PAGE 17
Mechanical Engineering MCQs- Page 17
1. Specific speed of Kaplan turbine ranges between
(A) 600 to 900 (B) 300 to 600 (C) 100 to 300 (D) 30 to 60
Ans: B
2. Kaplan turbine is
(A) A high head mixed flow turbine (B) a low head axial flow turbine
(C) an impulse inward flow turbine (D) an outward flow reaction turbine
Ans: B
3. If there are m physical quantities and n fundamental dimensions in a particular process, the number of non-dimensional parameters is
(A) m – n (B) m + n (C) m x n (D) m / n
Ans: A
4. In order to have maximum power from a Pelton turbine, the bucket speed must be
(A) Equal to twice the jet speed (B) Equal to the jet speed (C) Equal to half of the jet speed (D) One and a half times the jet speed
Ans: C
5. The unit of elastic modulus is the same as those of
(A) strain, shear modulus and force (B) shear modulus, stress and force
(C) stress, shear modulus and pressure (D) stress, strain and pressure
Ans: C
6. The total momentum of a system of masses (i.e. moving bodies) in any one direction remains constant, unless acted upon by an external force in that direction. This statement is called
(A) Newton’s first law of motion (B) Newton’s second law of motion
(C) principle of conservation of energy (D) principle of conservation of momentum
Ans: D
7. For a fully developed flow through a pipe, the ratio of the maximum velocity to the average velocity is
(A) 1 (B) 2 (C) 1.42 (D) 4
Ans: B
8. Starting friction is low in
(A) Boundary lubrication (B) Mixed (or semi fluid) lubrication (C) Hydrostatic lubrication (D) Hydrodynamic lubrication
Ans: C
9. In thick film hydrodynamic journal bearings, the coefficient of friction
(A) Decreases with increase in load (B) Increases with increase in load
(C) Decreases with increase in speed (D) Independent of speed or load
Ans: A
10. For full depth of involute spur gears, minimum number of teeth of pinion to avoid interference depends upon
(A) Pressure angle (B) Circular pitch (C) Pitch diameter (D) Aspect ratio
Ans: A
11. Large speed reductions (greater than 20) in one stage of a gear train are possible through
(A) Helical gearing (B) Bevel gearing (C) Spur gearing (D) Worm gearing
Ans: D
12. Which one of the following is used to convert a rotational motion into a translational motion?
(A) Worm gears (B) Double helical gears (C) Rack and pinion gears (D) Bevel gears
Ans: C
13. In a Newtonian fluid shear stress is
(A) Inversely proportional to the velocity gradient (B) Directly proportional to the velocity gradient
(C) Independent of the velocity gradient (D) Practically zero
Ans: B
14. With the increase in pressure ratio thermal efficiency of a simple gas turbine plant with fixed turbine inlet temperature
(A) Increases (B) Decreases (C) First increases and then decreases (D) First decreases and then increases
Ans: A
15. Greater the difference between jet velocity and aeroplane velocity
(A) Less the propulsive efficiency (B) Greater the propulsive efficiency
(C) Unaffected is the propulsive efficiency (D) None of the above.
Ans: A
16. A circular solid disc of uniform thickness 20mm, radius 200mm and mass 20kg is used as a fly wheel. If it rotates at 600rpm, the kinetic energy of the fly wheel, in Joules is
(A) 3160 (B) 1580 (C) 790 (D) 395
Ans: C
17. The spring constant of a helical compression spring does not depend on
(A) Wire diameter (B) Number of active turns (C) Coil diameter (D) Material strength
Ans: D
18. The crystal structure of austenite is
(A) body centered cubic (B) face centered cubic (C) hexagonal close packed (D) body centered tetragonal
Ans: B
19. Which of the following operation does not use a jig
(A) drilling (B) reaming (C) turning (D) tapping
Ans: C
20. In a spring mass-system, the mass is m and the spring constant is k. the critical damping coefficient of the system is 0.1 kg/s. In another spring-mass system, the mass is 2m and the spring constant is 8k. the critical damping coefficient ( in kg/s) of this system is
(A) 1.6 (B) 0.8 (C) 0.4 (D) 0.2
Ans: C
21. In a structure subjected to fatigue loading, the minimum and maximum stresses developed in a cycle are 200MPa and 400MPa respectively. The value of stress amplitude (in MPa) is
(A) 600 (B) 300 (C) 200 (D) 100
Ans: D
22. The process of shot peening increases the fatigue life of steel springs mainly because it results in
(A) Damping of vibration (B) Surface hardening (C) Increased stiffness of the material (D) Residual compression at the surface
Ans: D
23. A streamlined body is defined as a body about which
(A) The vortex drag is zero (B) The flow is along the streamlines
(C) The flow separation is suppressed (D) The flow is laminar
Ans: C
24. An autocollimator is used to
(A) measure small angular displacements on flat surface (B) compare known and unknown dimensions
(C) measure the flatness error (D) measure roundness error between centers
Ans: A
25. In which one of the following machining manual part programming is done?
(A) CNC machining (B) NC machining (C) DNC machining (D) FMS machining
Ans: B
26. A single-phase full wave rectifier is a
(A) single pulse rectifier (B) multiple pulse rectifier (C) two pulse rectifier (D) three pulse rectifier
Ans: C
27. PERT is a technique which is:
(A) event oriented (B) activity oriented (C) time oriented (D) work oriented
Ans: A
28. NavierStoke’s equation represents the conservation of
(A) Mass (B) Momentum (C) Pressure (D) Energy
Ans: B
29. Within boundary layer for a steady incompressible flow, the Bernoulli equation
(A) holds because the flow is steady (B) holds because the flow is transitional
(C) holds because the flow is incompressible (D) does not hold because the flow is frictional
Ans: D
30. The parameters which determine the friction factor for turbulent flow in a rough pipe are
(A) Froude number and relative roughness (B) Reynolds number and relative roughness
(C) Mach number and relative roughness (D) Froude number and Mach number
Ans: B
31. The shear stress at a point in a shaft subjected to a torque
(A) directly proportional to the polar moment of inertia and to the distance of the point from the axis
(B) directly proportional to the applied torque and inversely proportional to the polar moment of inertia
(C) directly proportional to the applied torque and the polar moment of inertia
(D) inversely proportional to the applied torque and the polar moment of inertia
Ans: B
32. The coefficient of restitution for inelastic bodies is
(A) zero (B) one (C) between zero and one (D) more than one
Ans: A
33. In a reverted gear train
(A) one gear is always fixed (B) the axes of the first and the last gear are co-axial
(C) at least one of the gear axis is in motion (D) the axes of the first and the last gear are parallel
Ans: B
34. Carbide tipped tools usually have
(A) negative rake angle (B) positive rake angle (C) any rake angle (D) no rake angle
Ans: A
35. In order to have interference fit, it is essential that the lower limit of the shaft should be
(A) greater than the upper limit of the hole (B) lesser than the upper limit of the hole
(C) greater than the lower limit of the hole (D) lesser than the lower limit of the hole
Ans: A
36. If the doping level of a crystal diode is increased, the breakdown voltage:
(A) remains the same (B) increased (C) decreased (D) none of the above
Ans: C
37. Which one of the following is NOT a work measurement technique?
(A) time study (B) work sampling (C) motion time data (D) micromotion study
Ans: D
38. Which of the following process is represented by a horizontal line parallel to the abscissa of a Mollier-diagram?
(A) constant pressure (B) constant temperature (C) free expansion on throttling (D) adiabatic expansion
Ans: C
39. For evaporators and condensers, for the given conditions, the logarithmic mean temperature difference (LMTD) for parallel flow is
(A) equal to that for counter flow (B) greater than that for counter flow
(C) smaller than that for counter flow (D) very much smaller than that for counter flow
Ans: A
40. The predominant forces acting on an element of fluid in the boundary layer over a flat plate in a uniform parallel stream are
(A) Viscous and inertia forces (B) Inertial and parallel forces (C) Viscous and pressure forces (D) Viscous and body forces
Ans: A
41. The internal energy of an ideal gas is a function of
(A) pressure only (B) pressure and volume (C) pressure, volume and temperature (D) absolute temperature only
Ans: D
42. For laminar flow through a long pipe, the pressure drop per unit length increases
(A) In linear proportion to the cross sectional area (B) In inverse proportion to the cross sectional area
(C) In proportion to the diameter of the pipe (D) In inverse proportion to the square of cross sectional area
Ans: B
43. Three metal walls of same wall thickness and cross-sectional area have thermal conductivities k, 2k and 3k respectively. For the same heat transfers, the temperature drops across the wall will be in the ratio
(A) 1:2:3
(B) 3:2:1
(C) 1:1:1
(D) temperature drop ratios cannot be worked out as the given data is insufficient
Ans: B
44. A discontinuous real function can be expressed as
(A) Taylor’s series and Fourier series
(B) Taylor’s series and not by Fourier’s series
(C) neither Taylor’s series nor Fourier’s series
(D) not by Taylor’s series, but by Fourier’s series
Ans: D
45. Cavitation occurs when:
(A) pressure at any point in the flow approaches atmospheric pressure
(B) pressure at any point in the flow approaches critical pressure
(C) pressure at any point in the flow falls below the vapour pressure at prevailing temperature
(D) pressure at any point in the flow becomes above the vapour pressure at prevailing temperature
Ans: C
46. A gas turbine cycle with heat exchanger and reheating improves
(A) only the thermal efficiency (B) only the specific power output
(C) both thermal efficiency and specific power output (D) neither thermal efficiency nor specific power output
Ans: C
47. In I. C. engine, Supercharging is used for:
(A) supplying compressed air to remove combustion products (B) providing forced cooling to avoid excessive heating
(C) supplying air to the engine at higher density to increase its mass (D) injecting excess fuel for more load
Ans: C
48. The refrigerant used in steam jet refrigeration is
(A) ammonia (B) freon-22 (C) water (D) brine
Ans: C
49. Fins are usually provided to a heat exchanger surface in order to augment heat transfer by increasing the
(A) heat transfer coefficient (B) surface area (C) turbulence level (D) temperature difference
Ans: B
50. Stokes theorem connects
(A) a line integral and a surface integral (B) a surface integral and a volume integral
(C) a line integral and a volume integral (D) gradient of a function and its surface integral
Ans: A
(A) 600 to 900 (B) 300 to 600 (C) 100 to 300 (D) 30 to 60
Ans: B
2. Kaplan turbine is
(A) A high head mixed flow turbine (B) a low head axial flow turbine
(C) an impulse inward flow turbine (D) an outward flow reaction turbine
Ans: B
3. If there are m physical quantities and n fundamental dimensions in a particular process, the number of non-dimensional parameters is
(A) m – n (B) m + n (C) m x n (D) m / n
Ans: A
4. In order to have maximum power from a Pelton turbine, the bucket speed must be
(A) Equal to twice the jet speed (B) Equal to the jet speed (C) Equal to half of the jet speed (D) One and a half times the jet speed
Ans: C
5. The unit of elastic modulus is the same as those of
(A) strain, shear modulus and force (B) shear modulus, stress and force
(C) stress, shear modulus and pressure (D) stress, strain and pressure
Ans: C
6. The total momentum of a system of masses (i.e. moving bodies) in any one direction remains constant, unless acted upon by an external force in that direction. This statement is called
(A) Newton’s first law of motion (B) Newton’s second law of motion
(C) principle of conservation of energy (D) principle of conservation of momentum
Ans: D
7. For a fully developed flow through a pipe, the ratio of the maximum velocity to the average velocity is
(A) 1 (B) 2 (C) 1.42 (D) 4
Ans: B
8. Starting friction is low in
(A) Boundary lubrication (B) Mixed (or semi fluid) lubrication (C) Hydrostatic lubrication (D) Hydrodynamic lubrication
Ans: C
9. In thick film hydrodynamic journal bearings, the coefficient of friction
(A) Decreases with increase in load (B) Increases with increase in load
(C) Decreases with increase in speed (D) Independent of speed or load
Ans: A
10. For full depth of involute spur gears, minimum number of teeth of pinion to avoid interference depends upon
(A) Pressure angle (B) Circular pitch (C) Pitch diameter (D) Aspect ratio
Ans: A
11. Large speed reductions (greater than 20) in one stage of a gear train are possible through
(A) Helical gearing (B) Bevel gearing (C) Spur gearing (D) Worm gearing
Ans: D
12. Which one of the following is used to convert a rotational motion into a translational motion?
(A) Worm gears (B) Double helical gears (C) Rack and pinion gears (D) Bevel gears
Ans: C
13. In a Newtonian fluid shear stress is
(A) Inversely proportional to the velocity gradient (B) Directly proportional to the velocity gradient
(C) Independent of the velocity gradient (D) Practically zero
Ans: B
14. With the increase in pressure ratio thermal efficiency of a simple gas turbine plant with fixed turbine inlet temperature
(A) Increases (B) Decreases (C) First increases and then decreases (D) First decreases and then increases
Ans: A
15. Greater the difference between jet velocity and aeroplane velocity
(A) Less the propulsive efficiency (B) Greater the propulsive efficiency
(C) Unaffected is the propulsive efficiency (D) None of the above.
Ans: A
16. A circular solid disc of uniform thickness 20mm, radius 200mm and mass 20kg is used as a fly wheel. If it rotates at 600rpm, the kinetic energy of the fly wheel, in Joules is
(A) 3160 (B) 1580 (C) 790 (D) 395
Ans: C
17. The spring constant of a helical compression spring does not depend on
(A) Wire diameter (B) Number of active turns (C) Coil diameter (D) Material strength
Ans: D
18. The crystal structure of austenite is
(A) body centered cubic (B) face centered cubic (C) hexagonal close packed (D) body centered tetragonal
Ans: B
19. Which of the following operation does not use a jig
(A) drilling (B) reaming (C) turning (D) tapping
Ans: C
20. In a spring mass-system, the mass is m and the spring constant is k. the critical damping coefficient of the system is 0.1 kg/s. In another spring-mass system, the mass is 2m and the spring constant is 8k. the critical damping coefficient ( in kg/s) of this system is
(A) 1.6 (B) 0.8 (C) 0.4 (D) 0.2
Ans: C
21. In a structure subjected to fatigue loading, the minimum and maximum stresses developed in a cycle are 200MPa and 400MPa respectively. The value of stress amplitude (in MPa) is
(A) 600 (B) 300 (C) 200 (D) 100
Ans: D
22. The process of shot peening increases the fatigue life of steel springs mainly because it results in
(A) Damping of vibration (B) Surface hardening (C) Increased stiffness of the material (D) Residual compression at the surface
Ans: D
23. A streamlined body is defined as a body about which
(A) The vortex drag is zero (B) The flow is along the streamlines
(C) The flow separation is suppressed (D) The flow is laminar
Ans: C
24. An autocollimator is used to
(A) measure small angular displacements on flat surface (B) compare known and unknown dimensions
(C) measure the flatness error (D) measure roundness error between centers
Ans: A
25. In which one of the following machining manual part programming is done?
(A) CNC machining (B) NC machining (C) DNC machining (D) FMS machining
Ans: B
26. A single-phase full wave rectifier is a
(A) single pulse rectifier (B) multiple pulse rectifier (C) two pulse rectifier (D) three pulse rectifier
Ans: C
27. PERT is a technique which is:
(A) event oriented (B) activity oriented (C) time oriented (D) work oriented
Ans: A
28. NavierStoke’s equation represents the conservation of
(A) Mass (B) Momentum (C) Pressure (D) Energy
Ans: B
29. Within boundary layer for a steady incompressible flow, the Bernoulli equation
(A) holds because the flow is steady (B) holds because the flow is transitional
(C) holds because the flow is incompressible (D) does not hold because the flow is frictional
Ans: D
30. The parameters which determine the friction factor for turbulent flow in a rough pipe are
(A) Froude number and relative roughness (B) Reynolds number and relative roughness
(C) Mach number and relative roughness (D) Froude number and Mach number
Ans: B
31. The shear stress at a point in a shaft subjected to a torque
(A) directly proportional to the polar moment of inertia and to the distance of the point from the axis
(B) directly proportional to the applied torque and inversely proportional to the polar moment of inertia
(C) directly proportional to the applied torque and the polar moment of inertia
(D) inversely proportional to the applied torque and the polar moment of inertia
Ans: B
32. The coefficient of restitution for inelastic bodies is
(A) zero (B) one (C) between zero and one (D) more than one
Ans: A
33. In a reverted gear train
(A) one gear is always fixed (B) the axes of the first and the last gear are co-axial
(C) at least one of the gear axis is in motion (D) the axes of the first and the last gear are parallel
Ans: B
34. Carbide tipped tools usually have
(A) negative rake angle (B) positive rake angle (C) any rake angle (D) no rake angle
Ans: A
35. In order to have interference fit, it is essential that the lower limit of the shaft should be
(A) greater than the upper limit of the hole (B) lesser than the upper limit of the hole
(C) greater than the lower limit of the hole (D) lesser than the lower limit of the hole
Ans: A
36. If the doping level of a crystal diode is increased, the breakdown voltage:
(A) remains the same (B) increased (C) decreased (D) none of the above
Ans: C
37. Which one of the following is NOT a work measurement technique?
(A) time study (B) work sampling (C) motion time data (D) micromotion study
Ans: D
38. Which of the following process is represented by a horizontal line parallel to the abscissa of a Mollier-diagram?
(A) constant pressure (B) constant temperature (C) free expansion on throttling (D) adiabatic expansion
Ans: C
39. For evaporators and condensers, for the given conditions, the logarithmic mean temperature difference (LMTD) for parallel flow is
(A) equal to that for counter flow (B) greater than that for counter flow
(C) smaller than that for counter flow (D) very much smaller than that for counter flow
Ans: A
40. The predominant forces acting on an element of fluid in the boundary layer over a flat plate in a uniform parallel stream are
(A) Viscous and inertia forces (B) Inertial and parallel forces (C) Viscous and pressure forces (D) Viscous and body forces
Ans: A
41. The internal energy of an ideal gas is a function of
(A) pressure only (B) pressure and volume (C) pressure, volume and temperature (D) absolute temperature only
Ans: D
42. For laminar flow through a long pipe, the pressure drop per unit length increases
(A) In linear proportion to the cross sectional area (B) In inverse proportion to the cross sectional area
(C) In proportion to the diameter of the pipe (D) In inverse proportion to the square of cross sectional area
Ans: B
43. Three metal walls of same wall thickness and cross-sectional area have thermal conductivities k, 2k and 3k respectively. For the same heat transfers, the temperature drops across the wall will be in the ratio
(A) 1:2:3
(B) 3:2:1
(C) 1:1:1
(D) temperature drop ratios cannot be worked out as the given data is insufficient
Ans: B
44. A discontinuous real function can be expressed as
(A) Taylor’s series and Fourier series
(B) Taylor’s series and not by Fourier’s series
(C) neither Taylor’s series nor Fourier’s series
(D) not by Taylor’s series, but by Fourier’s series
Ans: D
45. Cavitation occurs when:
(A) pressure at any point in the flow approaches atmospheric pressure
(B) pressure at any point in the flow approaches critical pressure
(C) pressure at any point in the flow falls below the vapour pressure at prevailing temperature
(D) pressure at any point in the flow becomes above the vapour pressure at prevailing temperature
Ans: C
46. A gas turbine cycle with heat exchanger and reheating improves
(A) only the thermal efficiency (B) only the specific power output
(C) both thermal efficiency and specific power output (D) neither thermal efficiency nor specific power output
Ans: C
47. In I. C. engine, Supercharging is used for:
(A) supplying compressed air to remove combustion products (B) providing forced cooling to avoid excessive heating
(C) supplying air to the engine at higher density to increase its mass (D) injecting excess fuel for more load
Ans: C
48. The refrigerant used in steam jet refrigeration is
(A) ammonia (B) freon-22 (C) water (D) brine
Ans: C
49. Fins are usually provided to a heat exchanger surface in order to augment heat transfer by increasing the
(A) heat transfer coefficient (B) surface area (C) turbulence level (D) temperature difference
Ans: B
50. Stokes theorem connects
(A) a line integral and a surface integral (B) a surface integral and a volume integral
(C) a line integral and a volume integral (D) gradient of a function and its surface integral
Ans: A
51. In flow through a nozzle, the Mach number is more than unity
(A) in the converging section (B) in the diverging section
(C) at the throat (D) can be in any section of the nozzle depending upon the nozzle profile and geometry
Ans: B
52. The efficiency of superheat Rankine cycle is higher than that of simple Rankine cycle because
(A) the enthalpy of main steam is higher for superheat cycle (B) the mean temperature of heat addition is higher for superheat cycle
(C) the temperature of steam in the condenser is high (D) the quality of steam in the condenser is low
Ans: B
53. For constant maximum pressure and heat input, the air standard efficiency of gas power cycles is in the order
(A) Diesel cycle, dual cycle, Otto cycle (B) Otto cycle, Diesel cycle, dual cycle
(C) Dual cycle, Otto cycle, Diesel cycle (D) Diesel cycle, Otto cycle, dual cycle
Ans: A
54. A stone of mass m at the end of a string of length ‘I’ is whirled in a vertical circle at a constant speed. The tension in the string will be maximum when the stone is
(A) at the top of the circle (B) half-way down from the top
(C) quarter-way down from the top (D) at the bottom of the circle
Ans: D
55. For a ductile material, toughness is a measure of
(A) resistance to scratching (B) ability to absorb energy up to fracture
(C) ability to absorb energy till elastic limit (D) resistance to indentation
Ans: B
56. The pitch point of a cam-follower mechanism is
(A) point on the cam pitch curve having the maximum pressure angle (B) any point on the pitch circle
(C) any point on the pitch curve (D) reference point on the follower for the purpose of laying the cam profile
Ans: A
57. Eigenvalues of a real symmetric matrix are always
(A) positive (B) negative (C) real (D) complex
Ans: C
58. Two hydraulic turbines having identical specific speed and effective head at the inlet. If the speed ratio (N1/N2) of the two turbines is 2, then the respective power ratio (P1/P2) is
(A) 1/2 (B) 1/4 (C) 1/8 (D) 1/16
Ans: B
59. For a given heat flow and for the same thickness, the temperature drop across the material will be maximum for
(A) Steel (B) Glass wool (C) Copper (D) Refractory bricks
Ans: B
60. With an increase in the thickness of insulation around a circular pipe, heat loss to surroundings due to
(A) Convection and conduction increases (B) Convection and conduction decreases
(C) Convection increases, while that due to conduction decreases (D) Convection decreases, while that due to conduction increases
Ans: C
61. In pool boiling the highest HTC occurs in
(A) Film boiling zone (B) Partial film boiling zone (C) Nucleate boiling zone (D) Subcooled boiling zone
Ans: C
62. Grashof number signifies the ratio of
(A) buoyancy force to inertia force (B) buoyancy force to viscous force
(C) buoyancy force to surface tension force (D) inertia force to viscous force
Ans: B
63. For the fluid flowing over a flat plate with Prandtl number greater than unity, the thermal boundary layer for laminar forced convection (A) is thinner than the hydrodynamic boundary layer (B) is thicker than the hydrodynamic boundary layer
(C) is of same thickness as the hydrodynamic boundary layer (D) has thickness equal to zero
Ans: A
64. Darcy- Weisbach equation gives relation between_________
(A) Pressure and temperature (B) Mass, volume and pressure (C) Head loss and pressure loss (D) Pressure loss only
Ans: C
65. Preheating before welding is done to
(A) Make the steel softer (B) Prevent cold cracks (C) prevent plate distortion (D) burn away oil, grease etc. from the plate surface
Ans: B
66. Two 1 mm thick steel sheets are to be spot welded at a current of 5000 A. Assuming effective resistance to be 200 micro-ohms and current flow time of 0.2 seconds, heat generated during the process will be
(A) 0.1 Joule (B) 0.2 Joule (C) 1000 Joule (D) 2000 Joule
Ans: C
67. Which of the following welding process results in the smallest heat affected zone
(A) Shielded metal arc welding (B) Gas welding (C) Laser beam welding (D) Thermite welding
Ans: C
68. Cutting tools are provided with large positive rake angle mainly for
(A) Reducing the magnitude of the cutting force (B) Increasing the strength of the cutting edge
(C) Avoiding rubbing action with the finished surface (D) Better heat dissipation
Ans: A
69. Friction at the tool-chip interface can be reduced by
(A) decreasing the rake angle (B) increasing the depth of cut (C) decreasing the cutting speed (D) increasing the cutting speed
Ans: D
70. When 1.0% plain carbon steel is slowly cooled from the molten state to 740 deg C, the resulting structure will contain
(A) Austenite and ferrite (B) Austenite and cementite (C) Ferrite and cementite (D) Pearlite and cementite
Ans: B
71. Increase in carbon content in plain carbon steel raises its
(A) Tensile strength and malleability (B) Tensile strength and hardness
(C) Ductility and ultimate tensile strength (D) Ductility and melting temperature
Ans: B
72. The most widely used reinforcement in modern day FRP tennis racket is
(A) Aluminum (B) Carbon fibre (C) Magnesium (D) Glass fibre
Ans: B
73. For the gas turbine system, the work ratio is defined as the ratio of
(A) actual heat drop and isentropic heat drop in a turbine (B) compressor work and turbine work
(C) net work output and turbine work (D) net work output and compressor work
Ans: C
74. A refrigerating machine working on reversed Carnot cycle takes out 2 kW per minute of heat from the system while working between temperature limits of 300 K and 200 K. COP and power consumed by the cycle will be
(A) 1, 1 kW (B) 1, 2 kW (C) 2, 1 kW (D) 2, 2 kW
Ans: C
75. For an isochronous governor, sensitiveness is equal to:
(A) 0 (B) 0.5 (C) 1.0 (D) ∞
Ans: D
76. In a simple truss, if n is the total number of joints, the total number of members is equal to
(A) 2n + 3 (B) 2n – 3 (C) n + 3 (D) n – 3
Ans: B
77. The load carrying capacity of a hydrodynamically lubricated journal bearing depends on
(A) Speed only (B) Viscosity only (C) Radial clearance only (D) Speed, Radial clearance and Viscosity
Ans: D
78. A gas having negative Joule Thomson co-efficient (m < 0) when throttled will
(A) become cooler
(B) become warmer
(C) remain at the same temperature
(D) either become cooler or warmer depending on the type of gas
Ans: B
79. The efficiency of the vapour power Rankine cycle can be increased by
(1) increasing the temperature of the working fluid at which heat is added. (2) increasing the pressure of the working fluid at which heat is added.
(3) decreasing the temperature of the working fluid at which heat is rejected.
Which of these statements is/are correct?
(A) 2 and 3 (B) 1 alone
(C) 1 and 2 (D) 1, 2 and 3
Ans: D
80. The preference of diesel engines for road transport is due to
(A) Easy starting (B) low specific fuel consumption over a large range of load
(C) complete combustion of charge (D) harmless exhaust
Ans: B
81. Velocity of flame propagation in the SI engine is maximum for air fuel mixture which is ____________ stoichiometric.
(A) 10% richer than (B) equal to (C) more than 10% richer than (D) 10% leaner than
Ans: A
82. Pressure vessel is said to be a thin cylindrical shell, if the ratio of the wall thickness of the shell to its diameter is
(A) equal to 1/10 (B) less than 1/10 (C) more than 1/10 (D) none of these
Ans: B
83. A circular shaft is subjected to a torque 'T' and a Bending moment 'M'. The ratio of maximum shear stress to maximum bending stress is
(A) 2 M/T (B) T/2M (C) 2T/M (D) M/2T
Ans: B
84. Reheat cycle is essential in a steam power plant to
(A) utilize the heat of flue gases
(B) heat the feed water on its way to boiler
(C) increase the plant efficiency
(D) to reduce the moisture content at the low pressure stages of turbines so that erosion and corrosion problems can be eliminated.
Ans: D
85. When air is adiabatically saturated, the temperature attained is
(A) dew point temperature (B) dry bulb temperature (C) wet bulb temperature (D) triple point temperature
Ans: C
86. Speed of sound is maximum in
(A) Liquid (B) Gas (C) Solid (D) Semisolid
Ans: C
87. Dew point temperature is the temperature at which condensation begins when the air is cooled at constant
(A) Volume (B) Entropy (C) Pressure (D) Enthalpy
Ans: C
88. Moist air at 35°C and 100% relative humidity is entering a psychometric device and leaving at 25°C and 100% relative humidity. The name of device is
(A) Humidifier (B) Dehumidifier (C) Sensible heating (D) Sensible cooling
Ans: B
89. At the point of boundary layer separation
(A) shear stress is maximum (B) shear stress is zero (C) velocity is negative (D) density variation is maximum
Ans: B
90. Consider the following properties:
1. Temperature 2. Viscosity 3. Specific entropy 4. Thermal Conductivity
Which of the above properties of a system is/are intensive?
(A) 1 only (B) 2 and 3 only (C) 2, 3 and 4 only (D) 1, 2, 3 and 4
Ans: D
91. Poisson's ratio of perfectly linear elastic material is
(A) 0 (B) 1 (C) 0.3 (D) 0.5
Ans: B
92. A solid shaft is used to transmit a power of 120 p kW at 120 rpm. The torque transmitted by the shaft is
(A) 30 kNm (B) 60 kNm (C) 90 kNm (D) 120 kNm
Ans: A
93. Antifriction bearings are
(A) journal bearing (B) pedestal bearing (C) collar bearing (D) needle bearing
Ans: D
94. Law of Gearing is about
(A) Constant torque between meshed gears
(B) Constant force between meshed gears
(C) Constant moment between meshed gears
(D) Constant velocity between meshed gears
Ans: D
95. Coefficient of restitution of perfectly elastic body is
(A) 0 (B) 1 (C) 0.5 (D) Infinite
Ans: B
96. Viscosity of water in comparison to mercury is
(A) Lesser (B) Higher (C) Equal (D) Unpredictable
Ans: A
97. The internal energy of an ideal gas is a function of
(A) Temperature and pressure (B) Volume and pressure (C) Entropy and pressure (D) Temperature only
Ans: D
98. Joule-Thomson process is
(A) Throttling process (B) Heating process (C) Compression process (D) Expansion process
Ans: A
99. For a ductile material, toughness is a measure of
(A) Resistance to scratching
(B) Ability to absorb energy up to fracture
(C) Ability to absorb energy till elastic limit
(D) Resistance to indentation
Ans: B
100. Internal gears are manufactured by
(A) Hobbing (B) Shaping with pinion cutters (C) Shaping with rack cutter (D) Milling
Ans: B
(A) in the converging section (B) in the diverging section
(C) at the throat (D) can be in any section of the nozzle depending upon the nozzle profile and geometry
Ans: B
52. The efficiency of superheat Rankine cycle is higher than that of simple Rankine cycle because
(A) the enthalpy of main steam is higher for superheat cycle (B) the mean temperature of heat addition is higher for superheat cycle
(C) the temperature of steam in the condenser is high (D) the quality of steam in the condenser is low
Ans: B
53. For constant maximum pressure and heat input, the air standard efficiency of gas power cycles is in the order
(A) Diesel cycle, dual cycle, Otto cycle (B) Otto cycle, Diesel cycle, dual cycle
(C) Dual cycle, Otto cycle, Diesel cycle (D) Diesel cycle, Otto cycle, dual cycle
Ans: A
54. A stone of mass m at the end of a string of length ‘I’ is whirled in a vertical circle at a constant speed. The tension in the string will be maximum when the stone is
(A) at the top of the circle (B) half-way down from the top
(C) quarter-way down from the top (D) at the bottom of the circle
Ans: D
55. For a ductile material, toughness is a measure of
(A) resistance to scratching (B) ability to absorb energy up to fracture
(C) ability to absorb energy till elastic limit (D) resistance to indentation
Ans: B
56. The pitch point of a cam-follower mechanism is
(A) point on the cam pitch curve having the maximum pressure angle (B) any point on the pitch circle
(C) any point on the pitch curve (D) reference point on the follower for the purpose of laying the cam profile
Ans: A
57. Eigenvalues of a real symmetric matrix are always
(A) positive (B) negative (C) real (D) complex
Ans: C
58. Two hydraulic turbines having identical specific speed and effective head at the inlet. If the speed ratio (N1/N2) of the two turbines is 2, then the respective power ratio (P1/P2) is
(A) 1/2 (B) 1/4 (C) 1/8 (D) 1/16
Ans: B
59. For a given heat flow and for the same thickness, the temperature drop across the material will be maximum for
(A) Steel (B) Glass wool (C) Copper (D) Refractory bricks
Ans: B
60. With an increase in the thickness of insulation around a circular pipe, heat loss to surroundings due to
(A) Convection and conduction increases (B) Convection and conduction decreases
(C) Convection increases, while that due to conduction decreases (D) Convection decreases, while that due to conduction increases
Ans: C
61. In pool boiling the highest HTC occurs in
(A) Film boiling zone (B) Partial film boiling zone (C) Nucleate boiling zone (D) Subcooled boiling zone
Ans: C
62. Grashof number signifies the ratio of
(A) buoyancy force to inertia force (B) buoyancy force to viscous force
(C) buoyancy force to surface tension force (D) inertia force to viscous force
Ans: B
63. For the fluid flowing over a flat plate with Prandtl number greater than unity, the thermal boundary layer for laminar forced convection (A) is thinner than the hydrodynamic boundary layer (B) is thicker than the hydrodynamic boundary layer
(C) is of same thickness as the hydrodynamic boundary layer (D) has thickness equal to zero
Ans: A
64. Darcy- Weisbach equation gives relation between_________
(A) Pressure and temperature (B) Mass, volume and pressure (C) Head loss and pressure loss (D) Pressure loss only
Ans: C
65. Preheating before welding is done to
(A) Make the steel softer (B) Prevent cold cracks (C) prevent plate distortion (D) burn away oil, grease etc. from the plate surface
Ans: B
66. Two 1 mm thick steel sheets are to be spot welded at a current of 5000 A. Assuming effective resistance to be 200 micro-ohms and current flow time of 0.2 seconds, heat generated during the process will be
(A) 0.1 Joule (B) 0.2 Joule (C) 1000 Joule (D) 2000 Joule
Ans: C
67. Which of the following welding process results in the smallest heat affected zone
(A) Shielded metal arc welding (B) Gas welding (C) Laser beam welding (D) Thermite welding
Ans: C
68. Cutting tools are provided with large positive rake angle mainly for
(A) Reducing the magnitude of the cutting force (B) Increasing the strength of the cutting edge
(C) Avoiding rubbing action with the finished surface (D) Better heat dissipation
Ans: A
69. Friction at the tool-chip interface can be reduced by
(A) decreasing the rake angle (B) increasing the depth of cut (C) decreasing the cutting speed (D) increasing the cutting speed
Ans: D
70. When 1.0% plain carbon steel is slowly cooled from the molten state to 740 deg C, the resulting structure will contain
(A) Austenite and ferrite (B) Austenite and cementite (C) Ferrite and cementite (D) Pearlite and cementite
Ans: B
71. Increase in carbon content in plain carbon steel raises its
(A) Tensile strength and malleability (B) Tensile strength and hardness
(C) Ductility and ultimate tensile strength (D) Ductility and melting temperature
Ans: B
72. The most widely used reinforcement in modern day FRP tennis racket is
(A) Aluminum (B) Carbon fibre (C) Magnesium (D) Glass fibre
Ans: B
73. For the gas turbine system, the work ratio is defined as the ratio of
(A) actual heat drop and isentropic heat drop in a turbine (B) compressor work and turbine work
(C) net work output and turbine work (D) net work output and compressor work
Ans: C
74. A refrigerating machine working on reversed Carnot cycle takes out 2 kW per minute of heat from the system while working between temperature limits of 300 K and 200 K. COP and power consumed by the cycle will be
(A) 1, 1 kW (B) 1, 2 kW (C) 2, 1 kW (D) 2, 2 kW
Ans: C
75. For an isochronous governor, sensitiveness is equal to:
(A) 0 (B) 0.5 (C) 1.0 (D) ∞
Ans: D
76. In a simple truss, if n is the total number of joints, the total number of members is equal to
(A) 2n + 3 (B) 2n – 3 (C) n + 3 (D) n – 3
Ans: B
77. The load carrying capacity of a hydrodynamically lubricated journal bearing depends on
(A) Speed only (B) Viscosity only (C) Radial clearance only (D) Speed, Radial clearance and Viscosity
Ans: D
78. A gas having negative Joule Thomson co-efficient (m < 0) when throttled will
(A) become cooler
(B) become warmer
(C) remain at the same temperature
(D) either become cooler or warmer depending on the type of gas
Ans: B
79. The efficiency of the vapour power Rankine cycle can be increased by
(1) increasing the temperature of the working fluid at which heat is added. (2) increasing the pressure of the working fluid at which heat is added.
(3) decreasing the temperature of the working fluid at which heat is rejected.
Which of these statements is/are correct?
(A) 2 and 3 (B) 1 alone
(C) 1 and 2 (D) 1, 2 and 3
Ans: D
80. The preference of diesel engines for road transport is due to
(A) Easy starting (B) low specific fuel consumption over a large range of load
(C) complete combustion of charge (D) harmless exhaust
Ans: B
81. Velocity of flame propagation in the SI engine is maximum for air fuel mixture which is ____________ stoichiometric.
(A) 10% richer than (B) equal to (C) more than 10% richer than (D) 10% leaner than
Ans: A
82. Pressure vessel is said to be a thin cylindrical shell, if the ratio of the wall thickness of the shell to its diameter is
(A) equal to 1/10 (B) less than 1/10 (C) more than 1/10 (D) none of these
Ans: B
83. A circular shaft is subjected to a torque 'T' and a Bending moment 'M'. The ratio of maximum shear stress to maximum bending stress is
(A) 2 M/T (B) T/2M (C) 2T/M (D) M/2T
Ans: B
84. Reheat cycle is essential in a steam power plant to
(A) utilize the heat of flue gases
(B) heat the feed water on its way to boiler
(C) increase the plant efficiency
(D) to reduce the moisture content at the low pressure stages of turbines so that erosion and corrosion problems can be eliminated.
Ans: D
85. When air is adiabatically saturated, the temperature attained is
(A) dew point temperature (B) dry bulb temperature (C) wet bulb temperature (D) triple point temperature
Ans: C
86. Speed of sound is maximum in
(A) Liquid (B) Gas (C) Solid (D) Semisolid
Ans: C
87. Dew point temperature is the temperature at which condensation begins when the air is cooled at constant
(A) Volume (B) Entropy (C) Pressure (D) Enthalpy
Ans: C
88. Moist air at 35°C and 100% relative humidity is entering a psychometric device and leaving at 25°C and 100% relative humidity. The name of device is
(A) Humidifier (B) Dehumidifier (C) Sensible heating (D) Sensible cooling
Ans: B
89. At the point of boundary layer separation
(A) shear stress is maximum (B) shear stress is zero (C) velocity is negative (D) density variation is maximum
Ans: B
90. Consider the following properties:
1. Temperature 2. Viscosity 3. Specific entropy 4. Thermal Conductivity
Which of the above properties of a system is/are intensive?
(A) 1 only (B) 2 and 3 only (C) 2, 3 and 4 only (D) 1, 2, 3 and 4
Ans: D
91. Poisson's ratio of perfectly linear elastic material is
(A) 0 (B) 1 (C) 0.3 (D) 0.5
Ans: B
92. A solid shaft is used to transmit a power of 120 p kW at 120 rpm. The torque transmitted by the shaft is
(A) 30 kNm (B) 60 kNm (C) 90 kNm (D) 120 kNm
Ans: A
93. Antifriction bearings are
(A) journal bearing (B) pedestal bearing (C) collar bearing (D) needle bearing
Ans: D
94. Law of Gearing is about
(A) Constant torque between meshed gears
(B) Constant force between meshed gears
(C) Constant moment between meshed gears
(D) Constant velocity between meshed gears
Ans: D
95. Coefficient of restitution of perfectly elastic body is
(A) 0 (B) 1 (C) 0.5 (D) Infinite
Ans: B
96. Viscosity of water in comparison to mercury is
(A) Lesser (B) Higher (C) Equal (D) Unpredictable
Ans: A
97. The internal energy of an ideal gas is a function of
(A) Temperature and pressure (B) Volume and pressure (C) Entropy and pressure (D) Temperature only
Ans: D
98. Joule-Thomson process is
(A) Throttling process (B) Heating process (C) Compression process (D) Expansion process
Ans: A
99. For a ductile material, toughness is a measure of
(A) Resistance to scratching
(B) Ability to absorb energy up to fracture
(C) Ability to absorb energy till elastic limit
(D) Resistance to indentation
Ans: B
100. Internal gears are manufactured by
(A) Hobbing (B) Shaping with pinion cutters (C) Shaping with rack cutter (D) Milling
Ans: B
· UPSC Exam Syllabus- Mechanical Engineering
· Mechanical Engineering
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