MECHANICAL ENGINEERING- PAGE 16
Mechanical Engineering MCQs- Page 16
1. In shell and tube heat exchanger, baffles are used to
(A) Reduce fouling of the tube surface (B) Increase the mixing of fluid
(C) deflect the flow in desired direction (D) increase the heat transfer area
Ans: C
2. Hot oil is cooled from 80 degree celcius to 50 degree Celsius in an oil cooler which used air as a coolant. The air temperature rises from 30 to 40 degree Celsius. The designer uses a LMTD value of 26 degree Celsius. The type of heat exchanger is:
(A) parallel flow (B) double pipe (C) counter flow (D) cross flow
Ans: D
3. In certain heat exchanger , both the fluids have identical mass flow rate specific heat product. The hot fluid enters at 81 deg C and leaves at 53 deg C, and the cold fluid entering at 25 deg C leave at 58 deg C, the effectiveness of the HE is
(A) 0.06 (B) 0.20 (C) 0.50 (D) 1.00
Ans: C
4. In a counter flow heat exchanger, for the hot fluid the heat capacity = 2kJ/kgK, mass flow rate = 5kg/s, inlet temperature = 150°C, outlet temperature = 100°C. For the cold fluid heat capacity = 4kJ/kgK, mass flow rate = 10kg/s, inlet temp. = 20°C. Neglecting the heat transfer to the surroundings, the outlet temperature of the cold fluid in °C is
(A) 7.5 (B) 32.5 (C) 45.5 (D) 70.0
Ans: B
5. In a counter flow heat exchanger, hot fluid enters at 60°C and cold fluid leaves at 30°C. Mass flow rate of the hot fluid is 1kg/s and that the cold fluid is 2kg/s. specific heat of the hot fluid is 10k J/kgK and that of the cold fluid is 5k J/kgK . The Log Mean Temperature Difference (LMTD) for the heat exchanger in °C is :
(A) 15 (B) 30 (C) 35 (D) 45
Ans: B
6. Die for wire drawing are made of
(A) carbides (B) cast iron (C) wrought iron (D) mild steel
Ans: A
7. The least count of a metric vernier caliper having 25 divisions on Vernier scale, matching with 24 divisions of main scale (1 main scale divisions = 0.5 mm) is
(A) 0.005 mm (B) 0.01 mm (C) 0.02 mm (D) 0.005mm
Ans: C
8. In a C-E of BJT configuration, an emitter resistor is used for:
(A) stabilization (B) ac signal bypass (C) collector bias (D) higher gain
Ans: A
9. In ABC inventory control technique, maximum attention is given to those items which are
(A) surplus (B) more in demand (C) perishable in nature (D) costly
Ans: D
10. An industrial gas (cp = 1kJ/kgK) enters a parallel flow heat exchanger at 250°C with a flow rate of 2kg/s to heat a water stream. The water stream (cp = 4kJ/kgK) enters the heat exchanger at 50°C with a flow rate of 1 kg/s. The heat exchanger has an effectiveness of 0.75. The gas stream exit temperature will be
(A) 75°C (B) 100°C (C) 125°C (D) 150°C
Ans: B
11. Biot number signifies the ratio of
(A) Convective resistance in the fluid to conductive resistance in the solid
(B) Conductive resistance in the solid to convective resistance in the fluid
(C) Inertia force to viscous force in the fluid
(D) Buoyancy force to viscous force in the fluid
Ans: B
12. An insulated rigid vessel contains a mixture of fuel and air. The mixture is ignited by a minute spark. The contents of the vessel experience
(A) Increase in temperature, pressure and energy
(B) Decrease in temperature, pressure and energy
(C) Increase in temperature and pressure but no change in energy
(D) Increase in temperature and pressure but decrease in energy
Ans: C
13. Optical square is
(A) engineer’s square having stock and blade set at 90°
(B) a constant deviation prism having the angle of deviation between the incident ray and reflected ray, equal to 90°
(C) a constant deviation prism having the angle of deviation between the incident ray and reflected ray, equal to 45°
(D) used to produce interference fringes
Ans: C
14. If the z-axis and x-axis of CNC lathe provided with straight line controls, it is possible to carry out
(A) turning and facing only (B) turning, facing and taper turning (C) turning, facing and thread cutting (D) turning, facing and drilling
Ans: A
15. The standard time of an operation while conducting a time study is
(A) Mean observed time + Allowances
(B) Normal time + Allowances
(C) Mean observed time x Rating factor + Allowances
(D) Normal time x Rating factor + Allowances
Ans: C
16. During normalizing process of steel, the specimen is heated
(A) between the upper and lower critical temperature and cooled in still air
(B) above the upper critical temperature and cooled in furnace
(C) above the upper critical temperature and cooled in still air
(D) between the upper and lower critical temperature and cooled in furnace
Ans: C
17. Under what conditions, the change in the enthalpy of a system equals the heat supplied?
(A) constant volume (B) constant temperature (C) constant pressure (D) standard temperature-pressure conditions
Ans: C
18. For a given heat flow and for the same thickness, the temperature drop across the material will be maximum for
(A) copper (B) steel (C) glass wool (D) refractory brick
Ans: C
19. Which of the following is the extensive property of a thermodynamics system?
(A) Pressure (B) Temperature (C) Density (D) Volume
Ans: D
20. A process that does not involve heat is called
(A) Equilibrium process (B) Thermal process (C) Adiabatic process (D) Isothermal process
Ans: C
21. Kelvin - Plank’s statement deals with
(A) Conversion of heat into work (B) Conservation of energy (C) Conservation of heat (D) Conservation of mass
Ans: A
22. When gas is heated at constant pressure, the heat supplied is utilized in:
(A) increasing the internal energy of gas (B) doing some external energy of gas
(C) increasing the internal energy of gas and also for doing some external work (D) none of the above
Ans: C
23. In a counter flow heat exchange, cold fluid enters at 30° C and leaves at 50° C, whereas the hot fluid enters at 150° C and leaves at 130° C. The mean temperature difference for this case is
(A) 20°C (B) 80°C (C) 100°C (D) Indeterminate
Ans: C
24. If a function is continuous at a point its first derivative
(A) may or may not exist (B) exists always (C) will not exist (D) has a unique value
Ans: A
25. When starting a centrifugal pump, the delivery valve is kept
(A) fully open (B) half open (C) less than half open (D) fully closed
Ans: D
26. What is the flash point of a liquid fuel?
(A) the temperature at which the fuel ignites spontaneously with a bang
(B) the temperature at which the fuel emits vapours at a rate which produces an inflammable mixture with air
(C) the temperature at which the fuel ignites clearly
(D) the temperature at which the fuel ignites without a spark
Ans: B
27. The amount of moisture in air can be measured by
(A) mass spectrometer (B) sling psychrometer (C) thermistor (D) photometer
Ans: B
28. The thermal efficiency of theoretical Otto cycle
(A) Increases with increase in isentropic index y (B) Increases with increase in compression ratio
(C) Does not depend upon the pressure ratio (D) Follow s all the above
Ans: D
29. In a two stage gas turbine plant, with intercooling and reheating
(A) Both work ratio and thermal efficiency improve (B) Thermal efficiency improves but work ratio decreases
(C) Both work ratio and thermal efficiency decrease. (D) Work ratio improves but thermal efficiency decreases
Ans: D
30. A simple pendulum of length 5m, with its bob of mass 1 kg, is set in simple harmonic motion. As it passes through its mean position, the bob has a speed of 5 m/s. The net force on the bob at the mean position is
(A) Zero (B) 5N (C) 2.5N (D) 25N
Ans: A
31. Velocity profile in a turbulent flow is:
(A) Linear (B) Parabolic (C) Logarithmic (D) Hyperbolic
Ans: C
32. A gas turbine plant working on Joule cycle produces 4000 kW of power. If its work ratio is 40%, what is the power consumed by the compressor?
(A) 2000 kW (B) 4000 kW (C) 6000 kW (D) 8000 kW
Ans: C
33. Which fuel has an octane rating of 100?
(A) iso-octane (B) normal heptanes (C) methyl alcohol (D) ethyl fluid
Ans: A
34. One ton of refrigeration is equal to the refrigeration effect corresponding to melting of 1000 kg of ice
(A) in 1 hour (B) in 24 hours (C) in 1 minute (D) in 12 hours
Ans: B
35. The ratio of tension on the tight side to that of the slack side in a flat belt drive is
(A) An exponential function of the product of coefficient of friction and lap angle
(B) Proportional to the product of coefficient of friction and lap angle
(C) Proportional to lap angle
(D) Proportional to the coefficient of friction
Ans: A
36. If the principal stresses in a plane stress problem are 1= 100MPa, 2= 40MPa, the magnitude of the maximum shear stress (in MPa) will be
(A) 40 (B) 60 (C) 20 (D) 30
Ans: D
37. In terms of Poisson’s ratio of Young’s Modulus (E) to Shear Modulus (G) of elastic materialis
(A) 2(1 - µ)
(B) 2(1 + µ)
(C) 1/2(1 - µ)
(D) 1/2(1+ µ)
Ans: B
38. The process of reheating the martensitic steel to reduce its brittleness without any significant loss in its hardness is
(A) Normalising (B) Annealing (C) Quenching (D) Tempering
Ans: D
39. The absolute zero temperature corresponds to the condition when
(A) Kinetic energy of gas molecules becomes zero
(B) All the substances exist only as solids
(C) Volume of a gas reduces to zero
(D) No pressure is exerted by the gas
Ans: A
40. A thin cylinder of inner radius 500 mm and thickness 10 mm subjected to an internal pressure of 5 MPa. The average circumferential (hoop) stress in MPa is
(A) 100 (B) 1000 (C) 250 (D) 500
Ans: C
41. If Poisson’s ratio of a material is 0.75, then the elastic modulus for the material is
(A) 3.5 times its shear modulus (B) 4 times its shear modulus
(C) equal to its shear modulus (D) 5 times its shear modulus
Ans: A
42. Stefan Boltzmann law is applicable for heat transfer by
(A) Conduction (B) Radiation (C) Convection (D) Conduction and radiation combined
Ans: B
43. The point, through which the whole weight of the body acts, irrespective of its position, is known as
(A) Moment of inertia (B) Centre of gravity (C) Centre of percussion (D) Centre of mass
Ans: B
44. The unbalanced force due to reciprocating masses
(A) varies in magnitude but constant in direction (B) varies in direction but constant in magnitude
(C) varies in magnitude and direction both (D) constant in magnitude and direction both
Ans: A
45. Which one of the following numbers represents the ratio of kinematic viscosity to the thermal diffusivity?
(A) Grashoff number (B) Prandtl number (C) Mach number (D) Nusselt number
Ans: B
46. Which of the following is an advantage of forging?
(A) good surface finish (B) improved physical property (C) low tooling cost (D) close tolerance
Ans: B
47. Reynold’s number is defined as the ratio of
(A) Inertia force to gravity force (B) Viscous force to gravity force
(C) Inertia force to viscous force (D) Viscous force to elastic force
Ans: C
48. The method of determination of indicated power of multi-cylinder SI engine is by the use of
(A) Morse test (B) Prony brake test (C) Motorint test (D) Heat balance test
Ans: A
49. The vapour compression refrigeration cycle operates on reversed
(A) Joule’ cycle (B) Atkinson cycle (C) Rankine cycle (D) Ericsson cycle
Ans: C
50. The shear force and bending moment diagrams for a cantilever beam carrying a concentrated load at free end will respectively be
(A) Triangle and rectangle (B) Triangle and parabola
(C) Rectangle and triangle (D) Rectangle and parabola
Ans: C
(A) Reduce fouling of the tube surface (B) Increase the mixing of fluid
(C) deflect the flow in desired direction (D) increase the heat transfer area
Ans: C
2. Hot oil is cooled from 80 degree celcius to 50 degree Celsius in an oil cooler which used air as a coolant. The air temperature rises from 30 to 40 degree Celsius. The designer uses a LMTD value of 26 degree Celsius. The type of heat exchanger is:
(A) parallel flow (B) double pipe (C) counter flow (D) cross flow
Ans: D
3. In certain heat exchanger , both the fluids have identical mass flow rate specific heat product. The hot fluid enters at 81 deg C and leaves at 53 deg C, and the cold fluid entering at 25 deg C leave at 58 deg C, the effectiveness of the HE is
(A) 0.06 (B) 0.20 (C) 0.50 (D) 1.00
Ans: C
4. In a counter flow heat exchanger, for the hot fluid the heat capacity = 2kJ/kgK, mass flow rate = 5kg/s, inlet temperature = 150°C, outlet temperature = 100°C. For the cold fluid heat capacity = 4kJ/kgK, mass flow rate = 10kg/s, inlet temp. = 20°C. Neglecting the heat transfer to the surroundings, the outlet temperature of the cold fluid in °C is
(A) 7.5 (B) 32.5 (C) 45.5 (D) 70.0
Ans: B
5. In a counter flow heat exchanger, hot fluid enters at 60°C and cold fluid leaves at 30°C. Mass flow rate of the hot fluid is 1kg/s and that the cold fluid is 2kg/s. specific heat of the hot fluid is 10k J/kgK and that of the cold fluid is 5k J/kgK . The Log Mean Temperature Difference (LMTD) for the heat exchanger in °C is :
(A) 15 (B) 30 (C) 35 (D) 45
Ans: B
6. Die for wire drawing are made of
(A) carbides (B) cast iron (C) wrought iron (D) mild steel
Ans: A
7. The least count of a metric vernier caliper having 25 divisions on Vernier scale, matching with 24 divisions of main scale (1 main scale divisions = 0.5 mm) is
(A) 0.005 mm (B) 0.01 mm (C) 0.02 mm (D) 0.005mm
Ans: C
8. In a C-E of BJT configuration, an emitter resistor is used for:
(A) stabilization (B) ac signal bypass (C) collector bias (D) higher gain
Ans: A
9. In ABC inventory control technique, maximum attention is given to those items which are
(A) surplus (B) more in demand (C) perishable in nature (D) costly
Ans: D
10. An industrial gas (cp = 1kJ/kgK) enters a parallel flow heat exchanger at 250°C with a flow rate of 2kg/s to heat a water stream. The water stream (cp = 4kJ/kgK) enters the heat exchanger at 50°C with a flow rate of 1 kg/s. The heat exchanger has an effectiveness of 0.75. The gas stream exit temperature will be
(A) 75°C (B) 100°C (C) 125°C (D) 150°C
Ans: B
11. Biot number signifies the ratio of
(A) Convective resistance in the fluid to conductive resistance in the solid
(B) Conductive resistance in the solid to convective resistance in the fluid
(C) Inertia force to viscous force in the fluid
(D) Buoyancy force to viscous force in the fluid
Ans: B
12. An insulated rigid vessel contains a mixture of fuel and air. The mixture is ignited by a minute spark. The contents of the vessel experience
(A) Increase in temperature, pressure and energy
(B) Decrease in temperature, pressure and energy
(C) Increase in temperature and pressure but no change in energy
(D) Increase in temperature and pressure but decrease in energy
Ans: C
13. Optical square is
(A) engineer’s square having stock and blade set at 90°
(B) a constant deviation prism having the angle of deviation between the incident ray and reflected ray, equal to 90°
(C) a constant deviation prism having the angle of deviation between the incident ray and reflected ray, equal to 45°
(D) used to produce interference fringes
Ans: C
14. If the z-axis and x-axis of CNC lathe provided with straight line controls, it is possible to carry out
(A) turning and facing only (B) turning, facing and taper turning (C) turning, facing and thread cutting (D) turning, facing and drilling
Ans: A
15. The standard time of an operation while conducting a time study is
(A) Mean observed time + Allowances
(B) Normal time + Allowances
(C) Mean observed time x Rating factor + Allowances
(D) Normal time x Rating factor + Allowances
Ans: C
16. During normalizing process of steel, the specimen is heated
(A) between the upper and lower critical temperature and cooled in still air
(B) above the upper critical temperature and cooled in furnace
(C) above the upper critical temperature and cooled in still air
(D) between the upper and lower critical temperature and cooled in furnace
Ans: C
17. Under what conditions, the change in the enthalpy of a system equals the heat supplied?
(A) constant volume (B) constant temperature (C) constant pressure (D) standard temperature-pressure conditions
Ans: C
18. For a given heat flow and for the same thickness, the temperature drop across the material will be maximum for
(A) copper (B) steel (C) glass wool (D) refractory brick
Ans: C
19. Which of the following is the extensive property of a thermodynamics system?
(A) Pressure (B) Temperature (C) Density (D) Volume
Ans: D
20. A process that does not involve heat is called
(A) Equilibrium process (B) Thermal process (C) Adiabatic process (D) Isothermal process
Ans: C
21. Kelvin - Plank’s statement deals with
(A) Conversion of heat into work (B) Conservation of energy (C) Conservation of heat (D) Conservation of mass
Ans: A
22. When gas is heated at constant pressure, the heat supplied is utilized in:
(A) increasing the internal energy of gas (B) doing some external energy of gas
(C) increasing the internal energy of gas and also for doing some external work (D) none of the above
Ans: C
23. In a counter flow heat exchange, cold fluid enters at 30° C and leaves at 50° C, whereas the hot fluid enters at 150° C and leaves at 130° C. The mean temperature difference for this case is
(A) 20°C (B) 80°C (C) 100°C (D) Indeterminate
Ans: C
24. If a function is continuous at a point its first derivative
(A) may or may not exist (B) exists always (C) will not exist (D) has a unique value
Ans: A
25. When starting a centrifugal pump, the delivery valve is kept
(A) fully open (B) half open (C) less than half open (D) fully closed
Ans: D
26. What is the flash point of a liquid fuel?
(A) the temperature at which the fuel ignites spontaneously with a bang
(B) the temperature at which the fuel emits vapours at a rate which produces an inflammable mixture with air
(C) the temperature at which the fuel ignites clearly
(D) the temperature at which the fuel ignites without a spark
Ans: B
27. The amount of moisture in air can be measured by
(A) mass spectrometer (B) sling psychrometer (C) thermistor (D) photometer
Ans: B
28. The thermal efficiency of theoretical Otto cycle
(A) Increases with increase in isentropic index y (B) Increases with increase in compression ratio
(C) Does not depend upon the pressure ratio (D) Follow s all the above
Ans: D
29. In a two stage gas turbine plant, with intercooling and reheating
(A) Both work ratio and thermal efficiency improve (B) Thermal efficiency improves but work ratio decreases
(C) Both work ratio and thermal efficiency decrease. (D) Work ratio improves but thermal efficiency decreases
Ans: D
30. A simple pendulum of length 5m, with its bob of mass 1 kg, is set in simple harmonic motion. As it passes through its mean position, the bob has a speed of 5 m/s. The net force on the bob at the mean position is
(A) Zero (B) 5N (C) 2.5N (D) 25N
Ans: A
31. Velocity profile in a turbulent flow is:
(A) Linear (B) Parabolic (C) Logarithmic (D) Hyperbolic
Ans: C
32. A gas turbine plant working on Joule cycle produces 4000 kW of power. If its work ratio is 40%, what is the power consumed by the compressor?
(A) 2000 kW (B) 4000 kW (C) 6000 kW (D) 8000 kW
Ans: C
33. Which fuel has an octane rating of 100?
(A) iso-octane (B) normal heptanes (C) methyl alcohol (D) ethyl fluid
Ans: A
34. One ton of refrigeration is equal to the refrigeration effect corresponding to melting of 1000 kg of ice
(A) in 1 hour (B) in 24 hours (C) in 1 minute (D) in 12 hours
Ans: B
35. The ratio of tension on the tight side to that of the slack side in a flat belt drive is
(A) An exponential function of the product of coefficient of friction and lap angle
(B) Proportional to the product of coefficient of friction and lap angle
(C) Proportional to lap angle
(D) Proportional to the coefficient of friction
Ans: A
36. If the principal stresses in a plane stress problem are 1= 100MPa, 2= 40MPa, the magnitude of the maximum shear stress (in MPa) will be
(A) 40 (B) 60 (C) 20 (D) 30
Ans: D
37. In terms of Poisson’s ratio of Young’s Modulus (E) to Shear Modulus (G) of elastic materialis
(A) 2(1 - µ)
(B) 2(1 + µ)
(C) 1/2(1 - µ)
(D) 1/2(1+ µ)
Ans: B
38. The process of reheating the martensitic steel to reduce its brittleness without any significant loss in its hardness is
(A) Normalising (B) Annealing (C) Quenching (D) Tempering
Ans: D
39. The absolute zero temperature corresponds to the condition when
(A) Kinetic energy of gas molecules becomes zero
(B) All the substances exist only as solids
(C) Volume of a gas reduces to zero
(D) No pressure is exerted by the gas
Ans: A
40. A thin cylinder of inner radius 500 mm and thickness 10 mm subjected to an internal pressure of 5 MPa. The average circumferential (hoop) stress in MPa is
(A) 100 (B) 1000 (C) 250 (D) 500
Ans: C
41. If Poisson’s ratio of a material is 0.75, then the elastic modulus for the material is
(A) 3.5 times its shear modulus (B) 4 times its shear modulus
(C) equal to its shear modulus (D) 5 times its shear modulus
Ans: A
42. Stefan Boltzmann law is applicable for heat transfer by
(A) Conduction (B) Radiation (C) Convection (D) Conduction and radiation combined
Ans: B
43. The point, through which the whole weight of the body acts, irrespective of its position, is known as
(A) Moment of inertia (B) Centre of gravity (C) Centre of percussion (D) Centre of mass
Ans: B
44. The unbalanced force due to reciprocating masses
(A) varies in magnitude but constant in direction (B) varies in direction but constant in magnitude
(C) varies in magnitude and direction both (D) constant in magnitude and direction both
Ans: A
45. Which one of the following numbers represents the ratio of kinematic viscosity to the thermal diffusivity?
(A) Grashoff number (B) Prandtl number (C) Mach number (D) Nusselt number
Ans: B
46. Which of the following is an advantage of forging?
(A) good surface finish (B) improved physical property (C) low tooling cost (D) close tolerance
Ans: B
47. Reynold’s number is defined as the ratio of
(A) Inertia force to gravity force (B) Viscous force to gravity force
(C) Inertia force to viscous force (D) Viscous force to elastic force
Ans: C
48. The method of determination of indicated power of multi-cylinder SI engine is by the use of
(A) Morse test (B) Prony brake test (C) Motorint test (D) Heat balance test
Ans: A
49. The vapour compression refrigeration cycle operates on reversed
(A) Joule’ cycle (B) Atkinson cycle (C) Rankine cycle (D) Ericsson cycle
Ans: C
50. The shear force and bending moment diagrams for a cantilever beam carrying a concentrated load at free end will respectively be
(A) Triangle and rectangle (B) Triangle and parabola
(C) Rectangle and triangle (D) Rectangle and parabola
Ans: C
51. Which one of the following instruments is a comparator?
(A) Tool Maker’s Microscope (B) GO/NO GO gauge (C) optical Interferometer (D) dial gauge
Ans: D
52. The most common interpolation methods in continuous path NC machining are
(A) linear and circular (B) linear and parabolic (C) circular and parabolic (D) circular and elliptic
Ans: A
53. The n-region has a greater concentration of _______ as compared to the p-region in a P-N junction diode.
(A) holes (B) electrons (C) both holes & electrons (D) phonons
Ans: B
54. Cold working of steel is defined as working
(A) below its recrystallisation temperature (B) above its recrystallisation temperature
(C) at its recrystallisation temperature (D) at zero kelvin
Ans: A
55. During normalizing process of steel, the specimen is heated
(A) above the upper critical temperature and cooled in still air (B) below the upper critical temperature and cooled in still air
(C) between the upper and lower critical temperature and cooled in furnace (D) above the upper critical temperature and cooled in furnace
Ans: A
56. A diffuse radiation surface has
(A) Radiation intensity independent of angle (B) Radiation intensity independent of both angle and wave length
(C) Emissive power independent of (D) Emissive power independent of wavelength
Ans: A
57. A 100 W electric bulb was switched on in a 2.5 m x 3 m x 3 m size thermally insulated room having a temperature of 20 deg C. The room temperature at the end of 24 hours will be
(A) 490 deg C (B) 470 deg C (C) 381 deg C (D) 361deg C
Ans: B
58. For a ductile material, toughness is a measure of
(A) ability to absorb energy up to elastic limit (B) ability to absorb energy up to fracture
(C) resistance to indentation (D) resistance to scratching
Ans: B
59. The process by which shell like casting (like toys)are made is
(A) shell moulding (B) centrifugal casting (C) slush casting (D) die casting
Ans: C
60. For feeding the liquid molten metal into the mould, converging passage is used
(A) to increase the rate of feeding (B) to reduce the wastage of cast metal
(C) to reduce air aspiration (D) to easily break off the protruding portion of casting
Ans: C
61. For casting of intricate shape turbine blades made of high strength alloys, the most suitable process is
(A) die casting (B) investment casting (C) slush casting (D) centrifugal casting
Ans: B
62. In a rolling process, sheet of 30 mm thickness is rolled to 21 mm thickness. Roll is of Diameter 800 mm and it rotates at 100 rpm. The roll strip contact length will be
(A) 60 mm (B) 63 mm (C) 80 mm (D) 90 mm
Ans: A
63. A source at a temperature of 500 K provides 1000 kJ of heat. The temperature of environment is 27 degree C. the maximum useful work (in kJ) that can be obtained from the heat source is
(A) 600 kJ (B) 500 kJ (C) 400 kJ (D) 270 kJ
Ans: C
64. A reversible heat engine receives 2 kJ of heat from a reservoir at 1000 K and a certain amount of heat from a reservoir at 800 K. It rejects 1 kJ of heat to a reservoir at 400 K. the net work output (in kJ) of the cycle is
(A) 0.8 (B) 1.0 (C) 1.4 (D) 2.0
Ans: C
65. A production line is said to be balanced when
(A) there are equal number of machines at each work station
(B) there are equal number of operators at each work station
(C) the waiting time for service at each station is the same
(D) the operation time at each station is the same
Ans: D
66. The effective number of lattice points in the unit cell of simple cubic, body centered cubic, and face centered cubic space lattices, respectively, are
(A) 1, 2, 2 (B) 1, 2, 4 (C) 2, 3, 4 (D) 2, 4, 4
Ans: B
67. An amount of 100 KW of heat is transferred through a wall in steady state. One side of the wall is maintained at 127oC and the other side at 27oC. The entropy generated (in W/K) due to the heat transfer through the wall is
(A) 30 W/K (B) 83.33 W/K (C) 100 W/K (D) 300 W/K
Ans: B
68. The heat removal rate from a refrigerated space and the power input to the compressor are 7.2 kW and 1.8 kW, respectively. The coefficient of performance (COP) of the refrigeratoris
(A) 4.0 (B) 3.0 (C) 0.75 (D) 0.25
Ans: A
69. A reversible cycle receives 40 kJ of heat from one heat source at a temperature of 127 deg C and 37 kJ from another heat source at 97oC. The heat rejected (in kJ) to the heat sink at 47 deg C is
(A) 64 kJ (B) 320 kJ (C) 640 kJ (D) 960 kJ
Ans: A
70. A heat reservoir at 900 K is brought into contact with the ambient at 300 K for a short time. During this period 9000 kJ of heat is lost by the heat reservoir. The total loss in availability due to this process is
(A) 2400 kJ (B) 1800 kJ (C) 6000 kJ (D) 9000 kJ
Ans: C
71. One side of a wall is maintained at 400 K and the other at 300 K. the rate of heat transfer through the wall is 1000 W and the surrounding temperature is 25oC. Assuming no generation of heat within the wall, the irreversibility (in W) due to heat transfer through the wall is
(A) 0.833 W (B) 248.23 W (C) 20.825 W (D) 25.833 W
Ans: B
72. The relationship (dT/dP)h = 0 holds good for
(A) An ideal gas at any state (B) A real gas at any state
(C) Any gas at its critical state (D) Any gas at its inversion point
Ans: D
73. At the triple point of a pure substance, the number of degrees of freedom is
(A) 0 (B) 1 (C) 2 (D) 3
Ans: A
74. Constant pressure lines in the super-heated region of the Mollier diagram will have
(A) A positive slope (B) A negative slope (C) Zero slope (D) Both positive and negative slope
Ans: A
75. Availability of a system at any given state is
(A) A property of the system
(B) The total energy of the system
(C) The maximum work obtainable as the system goes to dead state
(D) The maximum useful work obtainable as the system goes to dead state
Ans: D
76. A long thin walled cylindrical shell, closed at both ends, is subjected to an internal pressure. The ratio of the hoop stress (circumferential stress) to longitudinal stress developed in the shell is
(A) 0.0225 (B) 2.0 (C) 2.25 (D) 4.0
Ans: B
77. For a simply supported beam on two end supports the Bending Moment is maximum
(A) On the supports (B) At mid span (C) Where the deflection is maximum (D) Where there is no shear force
Ans: D
78. A concentrated load P acts on a simply supported beam of span L at a distance L/3 from the left support. The bending moment at the point of application of load is
(A) 2PL/3 (B) PL/3 (C) 2PL/9 (D) PL/9
Ans: C
79. The most commonly used moderator in nuclear power plants is
(A) heavy water (B) concrete and bricks (C) steel (D) graphite
Ans: D
80. Morse test is used to determine mechanical efficiency of:
(A) two stroke single cylinder engines (B) single cylinder C.I. engine
(C) 4 stroke single cylinder engine (D) multi cylinder engine
Ans: D
81. Flow separation past a solid object is caused by
(A) A negative pressure gradient (B) A positive pressure gradient
(C) The boundary layer thickness reducing to zero (D) A reduction of pressure to vapour pressure
Ans: B
82. During the adiabatic cooling of moist air
(A) DBT remains constant (B) specific humidity remains constant
(C) relative humidity remains constant (D) WBT remains constant
Ans: D
83. According to Lami’s theorem
(A) the three forces must be equal
(B) the three forces must be at 120° to each other
(C) the three forces must be in equilibrium
(D) if the three forces acting at a point are in equilibrium, then each force is proportional to the sine of the angle between the other two
Ans: D
84. The working surface above the pitch surface of the gear tooth is termed as
(A) addendum (B) dedendum (C) flank (D) face
Ans: D
85. Wax pattern is used in
(A) shell moulding (B) die casting (C) centrifugal casting (D) investment casting
Ans: D
86. Hardness of steel greatly improves with
(A) annealing (B) cyaniding (C) normalising (D) tempering
Ans: B
87. A feeler gauge is used to check the
(A) pitch of the screw (B) surface roughness (C) thickness of clearance (D) flatness of a surface
Ans: C
88. The central Processing Unit of a mini computer uses which of the following blocks 1. Memory unit 2. Control unit 3. Arithmetic unit 4. Output unit Select the correct answer using the codes given below:
(A) 1 and 2 (B) 1 and 3 (C) 2 and 3 (D) 1 and 4
Ans: C
89. The beams, one having square cross section and another circular cross section, are subjected to same amount of bending moment. If the cross section area and the material of both the beams are the same then
(A) Both beams will experience same deformation
(B) Maximum bending stress developed in both the beams is the same
(C) The circular beam experiences more bending stress than the square one.
(D) The square beam experiences more bending stress than the circular one
Ans: C
90. For a gas turbine the pressure ratio may be in the range
(A) 18 to 22 (B) 16 to 18 (C) 3 to 5 (D) 2 to 3
Ans: A
91. Which of these is the best description of a Zener diode?
(A) it works in the forward region (B) it is a rectifier diode (C) it is a constant electric current device (D) it is a constant voltage device
Ans: D
92. The bolts in a rigid flanged coupling connecting two shafts transmitting power are subjected to
(A) Shear force and bending moment (B) Axial force and torsion (C) Bending moment and torsion (D) Shear force only
Ans: A
93. The expected life of a ball bearing subjected to a load of 9800 N and working at 1000 rpm is 3000 hours. What is the expected life of the same bearing for a similar load of 4900 N and speed of 2000 rpm
(A) 3000 hours (B) 6000 hours (C) 9000 hours (D) 12000 hours
Ans: D
94. If the load on a ball bearing is reduced to half, the life of the ball bearing will
(A) Remain the same (B) Increase 2 times (C) Increase 4 times (D) Increase 8 times
Ans: D
95. Pitot tube is used to measure
(A) discharge (B) average velocity (C) pressure at a point (D) velocity at a point
Ans: D
96. A Bell-Coleman air refrigeration cycle works as a reversed:
(A) Stirling cycle (B) Otto cycle (C) Diesel cycle (D) Brayton cycle
Ans: D
97. Carburetion is done to:
(A) feed petrol into cylinder (B) govern the engine (C) break up and mix the petrol with air (D) heat up the charge to cylinder
Ans: C
98. For the same operating temperature limit and coefficient of performance (COP) of heat pump equals
(A) COP of refrigerator
(B) (COP of refrigerator)-1
(C) 1+ (COP of refrigerator)
(D) 1/(COP of refrigerator)
Ans: C
99. For laminar flow of a liquid in a smooth pipe at normal temperature and pressure, the pressure drop is
(A) Inversely proportional to density (B) directly proportional to density
(C) independent of density (D) proportional to square of density
Ans: C
100. Cavitation in a hydraulic reaction turbine is most likely to occur at the turbine
(A) Rotot exit (B) Exit (C) Stator exit (D) entry
Ans: A
(A) Tool Maker’s Microscope (B) GO/NO GO gauge (C) optical Interferometer (D) dial gauge
Ans: D
52. The most common interpolation methods in continuous path NC machining are
(A) linear and circular (B) linear and parabolic (C) circular and parabolic (D) circular and elliptic
Ans: A
53. The n-region has a greater concentration of _______ as compared to the p-region in a P-N junction diode.
(A) holes (B) electrons (C) both holes & electrons (D) phonons
Ans: B
54. Cold working of steel is defined as working
(A) below its recrystallisation temperature (B) above its recrystallisation temperature
(C) at its recrystallisation temperature (D) at zero kelvin
Ans: A
55. During normalizing process of steel, the specimen is heated
(A) above the upper critical temperature and cooled in still air (B) below the upper critical temperature and cooled in still air
(C) between the upper and lower critical temperature and cooled in furnace (D) above the upper critical temperature and cooled in furnace
Ans: A
56. A diffuse radiation surface has
(A) Radiation intensity independent of angle (B) Radiation intensity independent of both angle and wave length
(C) Emissive power independent of (D) Emissive power independent of wavelength
Ans: A
57. A 100 W electric bulb was switched on in a 2.5 m x 3 m x 3 m size thermally insulated room having a temperature of 20 deg C. The room temperature at the end of 24 hours will be
(A) 490 deg C (B) 470 deg C (C) 381 deg C (D) 361deg C
Ans: B
58. For a ductile material, toughness is a measure of
(A) ability to absorb energy up to elastic limit (B) ability to absorb energy up to fracture
(C) resistance to indentation (D) resistance to scratching
Ans: B
59. The process by which shell like casting (like toys)are made is
(A) shell moulding (B) centrifugal casting (C) slush casting (D) die casting
Ans: C
60. For feeding the liquid molten metal into the mould, converging passage is used
(A) to increase the rate of feeding (B) to reduce the wastage of cast metal
(C) to reduce air aspiration (D) to easily break off the protruding portion of casting
Ans: C
61. For casting of intricate shape turbine blades made of high strength alloys, the most suitable process is
(A) die casting (B) investment casting (C) slush casting (D) centrifugal casting
Ans: B
62. In a rolling process, sheet of 30 mm thickness is rolled to 21 mm thickness. Roll is of Diameter 800 mm and it rotates at 100 rpm. The roll strip contact length will be
(A) 60 mm (B) 63 mm (C) 80 mm (D) 90 mm
Ans: A
63. A source at a temperature of 500 K provides 1000 kJ of heat. The temperature of environment is 27 degree C. the maximum useful work (in kJ) that can be obtained from the heat source is
(A) 600 kJ (B) 500 kJ (C) 400 kJ (D) 270 kJ
Ans: C
64. A reversible heat engine receives 2 kJ of heat from a reservoir at 1000 K and a certain amount of heat from a reservoir at 800 K. It rejects 1 kJ of heat to a reservoir at 400 K. the net work output (in kJ) of the cycle is
(A) 0.8 (B) 1.0 (C) 1.4 (D) 2.0
Ans: C
65. A production line is said to be balanced when
(A) there are equal number of machines at each work station
(B) there are equal number of operators at each work station
(C) the waiting time for service at each station is the same
(D) the operation time at each station is the same
Ans: D
66. The effective number of lattice points in the unit cell of simple cubic, body centered cubic, and face centered cubic space lattices, respectively, are
(A) 1, 2, 2 (B) 1, 2, 4 (C) 2, 3, 4 (D) 2, 4, 4
Ans: B
67. An amount of 100 KW of heat is transferred through a wall in steady state. One side of the wall is maintained at 127oC and the other side at 27oC. The entropy generated (in W/K) due to the heat transfer through the wall is
(A) 30 W/K (B) 83.33 W/K (C) 100 W/K (D) 300 W/K
Ans: B
68. The heat removal rate from a refrigerated space and the power input to the compressor are 7.2 kW and 1.8 kW, respectively. The coefficient of performance (COP) of the refrigeratoris
(A) 4.0 (B) 3.0 (C) 0.75 (D) 0.25
Ans: A
69. A reversible cycle receives 40 kJ of heat from one heat source at a temperature of 127 deg C and 37 kJ from another heat source at 97oC. The heat rejected (in kJ) to the heat sink at 47 deg C is
(A) 64 kJ (B) 320 kJ (C) 640 kJ (D) 960 kJ
Ans: A
70. A heat reservoir at 900 K is brought into contact with the ambient at 300 K for a short time. During this period 9000 kJ of heat is lost by the heat reservoir. The total loss in availability due to this process is
(A) 2400 kJ (B) 1800 kJ (C) 6000 kJ (D) 9000 kJ
Ans: C
71. One side of a wall is maintained at 400 K and the other at 300 K. the rate of heat transfer through the wall is 1000 W and the surrounding temperature is 25oC. Assuming no generation of heat within the wall, the irreversibility (in W) due to heat transfer through the wall is
(A) 0.833 W (B) 248.23 W (C) 20.825 W (D) 25.833 W
Ans: B
72. The relationship (dT/dP)h = 0 holds good for
(A) An ideal gas at any state (B) A real gas at any state
(C) Any gas at its critical state (D) Any gas at its inversion point
Ans: D
73. At the triple point of a pure substance, the number of degrees of freedom is
(A) 0 (B) 1 (C) 2 (D) 3
Ans: A
74. Constant pressure lines in the super-heated region of the Mollier diagram will have
(A) A positive slope (B) A negative slope (C) Zero slope (D) Both positive and negative slope
Ans: A
75. Availability of a system at any given state is
(A) A property of the system
(B) The total energy of the system
(C) The maximum work obtainable as the system goes to dead state
(D) The maximum useful work obtainable as the system goes to dead state
Ans: D
76. A long thin walled cylindrical shell, closed at both ends, is subjected to an internal pressure. The ratio of the hoop stress (circumferential stress) to longitudinal stress developed in the shell is
(A) 0.0225 (B) 2.0 (C) 2.25 (D) 4.0
Ans: B
77. For a simply supported beam on two end supports the Bending Moment is maximum
(A) On the supports (B) At mid span (C) Where the deflection is maximum (D) Where there is no shear force
Ans: D
78. A concentrated load P acts on a simply supported beam of span L at a distance L/3 from the left support. The bending moment at the point of application of load is
(A) 2PL/3 (B) PL/3 (C) 2PL/9 (D) PL/9
Ans: C
79. The most commonly used moderator in nuclear power plants is
(A) heavy water (B) concrete and bricks (C) steel (D) graphite
Ans: D
80. Morse test is used to determine mechanical efficiency of:
(A) two stroke single cylinder engines (B) single cylinder C.I. engine
(C) 4 stroke single cylinder engine (D) multi cylinder engine
Ans: D
81. Flow separation past a solid object is caused by
(A) A negative pressure gradient (B) A positive pressure gradient
(C) The boundary layer thickness reducing to zero (D) A reduction of pressure to vapour pressure
Ans: B
82. During the adiabatic cooling of moist air
(A) DBT remains constant (B) specific humidity remains constant
(C) relative humidity remains constant (D) WBT remains constant
Ans: D
83. According to Lami’s theorem
(A) the three forces must be equal
(B) the three forces must be at 120° to each other
(C) the three forces must be in equilibrium
(D) if the three forces acting at a point are in equilibrium, then each force is proportional to the sine of the angle between the other two
Ans: D
84. The working surface above the pitch surface of the gear tooth is termed as
(A) addendum (B) dedendum (C) flank (D) face
Ans: D
85. Wax pattern is used in
(A) shell moulding (B) die casting (C) centrifugal casting (D) investment casting
Ans: D
86. Hardness of steel greatly improves with
(A) annealing (B) cyaniding (C) normalising (D) tempering
Ans: B
87. A feeler gauge is used to check the
(A) pitch of the screw (B) surface roughness (C) thickness of clearance (D) flatness of a surface
Ans: C
88. The central Processing Unit of a mini computer uses which of the following blocks 1. Memory unit 2. Control unit 3. Arithmetic unit 4. Output unit Select the correct answer using the codes given below:
(A) 1 and 2 (B) 1 and 3 (C) 2 and 3 (D) 1 and 4
Ans: C
89. The beams, one having square cross section and another circular cross section, are subjected to same amount of bending moment. If the cross section area and the material of both the beams are the same then
(A) Both beams will experience same deformation
(B) Maximum bending stress developed in both the beams is the same
(C) The circular beam experiences more bending stress than the square one.
(D) The square beam experiences more bending stress than the circular one
Ans: C
90. For a gas turbine the pressure ratio may be in the range
(A) 18 to 22 (B) 16 to 18 (C) 3 to 5 (D) 2 to 3
Ans: A
91. Which of these is the best description of a Zener diode?
(A) it works in the forward region (B) it is a rectifier diode (C) it is a constant electric current device (D) it is a constant voltage device
Ans: D
92. The bolts in a rigid flanged coupling connecting two shafts transmitting power are subjected to
(A) Shear force and bending moment (B) Axial force and torsion (C) Bending moment and torsion (D) Shear force only
Ans: A
93. The expected life of a ball bearing subjected to a load of 9800 N and working at 1000 rpm is 3000 hours. What is the expected life of the same bearing for a similar load of 4900 N and speed of 2000 rpm
(A) 3000 hours (B) 6000 hours (C) 9000 hours (D) 12000 hours
Ans: D
94. If the load on a ball bearing is reduced to half, the life of the ball bearing will
(A) Remain the same (B) Increase 2 times (C) Increase 4 times (D) Increase 8 times
Ans: D
95. Pitot tube is used to measure
(A) discharge (B) average velocity (C) pressure at a point (D) velocity at a point
Ans: D
96. A Bell-Coleman air refrigeration cycle works as a reversed:
(A) Stirling cycle (B) Otto cycle (C) Diesel cycle (D) Brayton cycle
Ans: D
97. Carburetion is done to:
(A) feed petrol into cylinder (B) govern the engine (C) break up and mix the petrol with air (D) heat up the charge to cylinder
Ans: C
98. For the same operating temperature limit and coefficient of performance (COP) of heat pump equals
(A) COP of refrigerator
(B) (COP of refrigerator)-1
(C) 1+ (COP of refrigerator)
(D) 1/(COP of refrigerator)
Ans: C
99. For laminar flow of a liquid in a smooth pipe at normal temperature and pressure, the pressure drop is
(A) Inversely proportional to density (B) directly proportional to density
(C) independent of density (D) proportional to square of density
Ans: C
100. Cavitation in a hydraulic reaction turbine is most likely to occur at the turbine
(A) Rotot exit (B) Exit (C) Stator exit (D) entry
Ans: A
· UPSC Exam Syllabus- Mechanical Engineering
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