MECHANICAL ENGINEERING- PAGE 13
Mechanical Engineering MCQs- Page 13
1. Chemically correct air-fuel ratio by mass for combustion of petrol is approximately
(a) 5 (b) 10 (c) 12 (d) 15
Ans: D
2. The efficiency of a Carnot engine depends on
(a) Type of fuel (b) Size of engine (c) Design of engine (d) Temperature of source and sink
Ans: D
3. Second law of thermodynamics defines
(a) Entropy (b) Enthalpy (c) Heat (d) Work
Ans: A
4. In an isothermal process, the internal energy
(a) increases (b) decreases (c) remains constant (d) first increases then decreases
Ans: C
5. Maximum work is done in compressing air when the compression is done in
(a) isothermal process (b) adiabatic process (c) polytropic process (d) None of these
Ans: B
6. What will be the volume of air at 327 °C if its volume at 27 °C is 1.5 m3 ?
(a) 3 m3 (b) 1.5 m3 (c) 6 m3 (d) 10 m3
Ans: A
7. Reciprocating air compressor is best suited for
(a) large quantity of air at high pressure (b) small quantity of air at high pressure
(c) small quantity of air at low pressure (d) large quantity of air at low pressure
Ans: B
8. Losses in a centrifugal compressor are due to
(a) inlet losses (b) impeller channel losses (c) diffuser losses (d) All of these
Ans: D
9. Which of the following cycles uses air as the refrigerant ?
(a) Ericsson (b) Stirling (c) Carnot (d) Bell-Coleman
Ans: D
10. One ton of refrigeration is equal to
(a) 210 kJ/min (b) 21 kJ/min (c) 420 kJ/min (d) 620 kJ/min
Ans: A
11. The refrigerant for a refrigerator should have
(a) high sensible heat (b) high total heat (c) high latent heat (d) low latent heat
Ans: C
12. If a heat pump cycle operates between the condenser temperature of +27 °C and evaporator temperature of – 23 °C, then the Carnot CoP will be
(a) 0.2 (b) 1.2 (c) 5 (d) 6
Ans: D
13. Which of the following refrigerants has lowest freezing point ?
(a) Freon – 12 (b) NH3 (c) CO2 (d) Freon-22
Ans: D
14. Thermal efficiency of an ideal diesel cycle
(a) increases with increase in cut-off ratio (b) decreases with increase in cut-off ratio
(c) does not depend on cut-off ratio (d) may increase or decrease with increase in cut-off ratio Ans: B
15. Indication of amount of moisture in air is given by
(a) dry bulb temperature (b) wet bulb temperature (c) dew point temperature (d) saturation temperature
Ans: B
16. As relative humidity decreases, the dew point will be
(a) lower than wet bulb temperature (b) higher than wet bulb temperature (c) equal to wet bulb temperature (d) None of these
Ans: A
17. Sensible heat is the heat needed to
(a) Vaporise water into steam and vice versa (b) Change the temperature of a liquid or vapour
(c) Convert water into steam and super heat it (d) Measure dew point temperature
Ans: B
18. Which of the following is the unit of entropy ?
(a) J/kg °k (b) Nm/kg sec (c) J/kg (d) Nm/sec
Ans: A
19. The difference of pressure between the inside and outside of a liquid drop is
(a) P = T × r (b) P = T/r (c) P = T/2r (d) P = 2T/r
Ans: D
20. Newton’s law of viscosity is a relationship between
(a) shear stress and rate of angular distortion (b) shear stress and viscosity
(c) pressure, velocity and viscosity (d) shear stress, pressure and rate of angular distortion
Ans: A
21. The curved lines on a psychrometric chart indicates
(a) specific humidity (b) relative humidity (c) DBT (d) WBT
Ans: B
22. Ratio of inertia force to surface tension is known as
(a) Mach number (b) Froude number (c) Reynold’s number (d) Weber’s number
Ans: D
23. Friction factor of pipes depends on
(a) rate of flow (b) fluid density (c) viscosity (d) All of these
Ans: D
24. Pelton wheels are used for minimum of following heads :
(a) 20 m (b) 150 m (c) 25 m (d) 200 m or above
Ans: D
25. Boiler rating is usually defined in terms of
(a) maximum temperature of steam (b) heat transfer rate kJ/hr
(c) heating surface area (d) heating output in kg/hr Ans: D
26. The melting point of the filler metal in brazing should be above
(a) 420 °C (b) 600 °C (c) 1530 °C (d) 800 °C
Ans: A
27. Moulding sands are graded according to their
(a) permeability (b) clay content and grain size (c) strength (d) None of these
Ans: B
28. Hot tear is related to
(a) casting defect (b) process of fabrication (c) heat treatment (d) welding of non-ferrous metals
Ans: A
29. Large and heavy castings are made by
(a) green sand moulding (b) pit moulding (c) dry sand moulding (d) pressure moulding
Ans: B
30. In which of the following welding process consumable electrode is used ?
(a) TIG (b) MIG (c) Thermit (d) Laser
Ans: B
31. Arc stability is better with
(a) AC welding (b) DC welding (c) Both AC & DC welding (d) None of these
Ans: B
32. Which of the following brazing joints is strongest ?
(a) Butt (b) Scarf (inclined) (c) Lap (d) All are equally strong.
Ans: C
33. The important property of a material in all metal forming processes is
(a) elasticity (b) plasticity (c) ductility (d) brittleness
Ans: B
34. Grate is the place in the boiler where
(a) fuel is burnt (b) pressure of steam is measured
(c) temperature of saturated steam is increased (d) None of the aboveAns: A
35. Spinning process is carried out by
(a) Hydraulic press (b) Mechanical press (c) Lathe (d) Milling machine
Ans: C
36. Which of the following process is used for gear finishing ?
(a) Hobbing (b) Shaping (c) Milling (d) Shaving or burnishing
Ans: D
37. The ductility of a material after work hardening
(a) increases (b) decreases (c) remains unaltered (d) None of these
Ans: B
38. Lathe bed is usually made of
(a) structural steel (b) stainless steel (c) cast iron (d) mild steel
Ans: C
39. In blanking operation, the angle of shear is provided on
(a) die (b) punch (c) both on punch and die (d) None of these
Ans: A
40. Tool life is most affected by
(a) cutting speed (b) tool geometry (c) feed and depth (d) None of these
Ans: A
41. On tool surface, crater wear occurs mainly due to
(a) abrasion (b) diffusion (c) oxidation (d) adhesion
Ans: B
42. In machining process, chips break due to
(a) plasticity (b) elasticity (c) work hardening (d) None of these
Ans: C
43. No cutting fluid is used while machining which metal ?
(a) Mild steel (b) Carbon steel (c) Aluminium (d) Cast iron
Ans: D
44. Which of the following metals can be easily drawn into wire ?
(a) Tin (b) Copper (c) Zinc (d) Cast iron
Ans: B
45. The composition of silver solder is
(a) silver, copper, zinc (b) silver, tin, zinc, nickel (c) silver, nickel (d) silver, copper, nickel
Ans: A
46. Muntz metal contains copper and zinc in the ratio of
(a) 50 : 50 (b) 40 : 60 (c) 60 : 40 (d) 80 : 20
Ans: C
47. In electro discharge machining the tool is made of
(a) tungsten carbide (b) diamond (c) copper or brass (d) stainless steel
Ans: C
48. The cutting tool used in spark erosion machining process is called
(a) arc (b) capacitor (c) electrode (d) dielectric
Ans: C
49. Anvil is made of which of the following metal ?
(a) Mild steel (b) Cast steel (c) Copper (d) Brass
Ans: B
50. Which of the following are discrete products ?
(a) Nut (b) Bolt (c) Screw (d) All of these
Ans: D
(a) 5 (b) 10 (c) 12 (d) 15
Ans: D
2. The efficiency of a Carnot engine depends on
(a) Type of fuel (b) Size of engine (c) Design of engine (d) Temperature of source and sink
Ans: D
3. Second law of thermodynamics defines
(a) Entropy (b) Enthalpy (c) Heat (d) Work
Ans: A
4. In an isothermal process, the internal energy
(a) increases (b) decreases (c) remains constant (d) first increases then decreases
Ans: C
5. Maximum work is done in compressing air when the compression is done in
(a) isothermal process (b) adiabatic process (c) polytropic process (d) None of these
Ans: B
6. What will be the volume of air at 327 °C if its volume at 27 °C is 1.5 m3 ?
(a) 3 m3 (b) 1.5 m3 (c) 6 m3 (d) 10 m3
Ans: A
7. Reciprocating air compressor is best suited for
(a) large quantity of air at high pressure (b) small quantity of air at high pressure
(c) small quantity of air at low pressure (d) large quantity of air at low pressure
Ans: B
8. Losses in a centrifugal compressor are due to
(a) inlet losses (b) impeller channel losses (c) diffuser losses (d) All of these
Ans: D
9. Which of the following cycles uses air as the refrigerant ?
(a) Ericsson (b) Stirling (c) Carnot (d) Bell-Coleman
Ans: D
10. One ton of refrigeration is equal to
(a) 210 kJ/min (b) 21 kJ/min (c) 420 kJ/min (d) 620 kJ/min
Ans: A
11. The refrigerant for a refrigerator should have
(a) high sensible heat (b) high total heat (c) high latent heat (d) low latent heat
Ans: C
12. If a heat pump cycle operates between the condenser temperature of +27 °C and evaporator temperature of – 23 °C, then the Carnot CoP will be
(a) 0.2 (b) 1.2 (c) 5 (d) 6
Ans: D
13. Which of the following refrigerants has lowest freezing point ?
(a) Freon – 12 (b) NH3 (c) CO2 (d) Freon-22
Ans: D
14. Thermal efficiency of an ideal diesel cycle
(a) increases with increase in cut-off ratio (b) decreases with increase in cut-off ratio
(c) does not depend on cut-off ratio (d) may increase or decrease with increase in cut-off ratio Ans: B
15. Indication of amount of moisture in air is given by
(a) dry bulb temperature (b) wet bulb temperature (c) dew point temperature (d) saturation temperature
Ans: B
16. As relative humidity decreases, the dew point will be
(a) lower than wet bulb temperature (b) higher than wet bulb temperature (c) equal to wet bulb temperature (d) None of these
Ans: A
17. Sensible heat is the heat needed to
(a) Vaporise water into steam and vice versa (b) Change the temperature of a liquid or vapour
(c) Convert water into steam and super heat it (d) Measure dew point temperature
Ans: B
18. Which of the following is the unit of entropy ?
(a) J/kg °k (b) Nm/kg sec (c) J/kg (d) Nm/sec
Ans: A
19. The difference of pressure between the inside and outside of a liquid drop is
(a) P = T × r (b) P = T/r (c) P = T/2r (d) P = 2T/r
Ans: D
20. Newton’s law of viscosity is a relationship between
(a) shear stress and rate of angular distortion (b) shear stress and viscosity
(c) pressure, velocity and viscosity (d) shear stress, pressure and rate of angular distortion
Ans: A
21. The curved lines on a psychrometric chart indicates
(a) specific humidity (b) relative humidity (c) DBT (d) WBT
Ans: B
22. Ratio of inertia force to surface tension is known as
(a) Mach number (b) Froude number (c) Reynold’s number (d) Weber’s number
Ans: D
23. Friction factor of pipes depends on
(a) rate of flow (b) fluid density (c) viscosity (d) All of these
Ans: D
24. Pelton wheels are used for minimum of following heads :
(a) 20 m (b) 150 m (c) 25 m (d) 200 m or above
Ans: D
25. Boiler rating is usually defined in terms of
(a) maximum temperature of steam (b) heat transfer rate kJ/hr
(c) heating surface area (d) heating output in kg/hr Ans: D
26. The melting point of the filler metal in brazing should be above
(a) 420 °C (b) 600 °C (c) 1530 °C (d) 800 °C
Ans: A
27. Moulding sands are graded according to their
(a) permeability (b) clay content and grain size (c) strength (d) None of these
Ans: B
28. Hot tear is related to
(a) casting defect (b) process of fabrication (c) heat treatment (d) welding of non-ferrous metals
Ans: A
29. Large and heavy castings are made by
(a) green sand moulding (b) pit moulding (c) dry sand moulding (d) pressure moulding
Ans: B
30. In which of the following welding process consumable electrode is used ?
(a) TIG (b) MIG (c) Thermit (d) Laser
Ans: B
31. Arc stability is better with
(a) AC welding (b) DC welding (c) Both AC & DC welding (d) None of these
Ans: B
32. Which of the following brazing joints is strongest ?
(a) Butt (b) Scarf (inclined) (c) Lap (d) All are equally strong.
Ans: C
33. The important property of a material in all metal forming processes is
(a) elasticity (b) plasticity (c) ductility (d) brittleness
Ans: B
34. Grate is the place in the boiler where
(a) fuel is burnt (b) pressure of steam is measured
(c) temperature of saturated steam is increased (d) None of the aboveAns: A
35. Spinning process is carried out by
(a) Hydraulic press (b) Mechanical press (c) Lathe (d) Milling machine
Ans: C
36. Which of the following process is used for gear finishing ?
(a) Hobbing (b) Shaping (c) Milling (d) Shaving or burnishing
Ans: D
37. The ductility of a material after work hardening
(a) increases (b) decreases (c) remains unaltered (d) None of these
Ans: B
38. Lathe bed is usually made of
(a) structural steel (b) stainless steel (c) cast iron (d) mild steel
Ans: C
39. In blanking operation, the angle of shear is provided on
(a) die (b) punch (c) both on punch and die (d) None of these
Ans: A
40. Tool life is most affected by
(a) cutting speed (b) tool geometry (c) feed and depth (d) None of these
Ans: A
41. On tool surface, crater wear occurs mainly due to
(a) abrasion (b) diffusion (c) oxidation (d) adhesion
Ans: B
42. In machining process, chips break due to
(a) plasticity (b) elasticity (c) work hardening (d) None of these
Ans: C
43. No cutting fluid is used while machining which metal ?
(a) Mild steel (b) Carbon steel (c) Aluminium (d) Cast iron
Ans: D
44. Which of the following metals can be easily drawn into wire ?
(a) Tin (b) Copper (c) Zinc (d) Cast iron
Ans: B
45. The composition of silver solder is
(a) silver, copper, zinc (b) silver, tin, zinc, nickel (c) silver, nickel (d) silver, copper, nickel
Ans: A
46. Muntz metal contains copper and zinc in the ratio of
(a) 50 : 50 (b) 40 : 60 (c) 60 : 40 (d) 80 : 20
Ans: C
47. In electro discharge machining the tool is made of
(a) tungsten carbide (b) diamond (c) copper or brass (d) stainless steel
Ans: C
48. The cutting tool used in spark erosion machining process is called
(a) arc (b) capacitor (c) electrode (d) dielectric
Ans: C
49. Anvil is made of which of the following metal ?
(a) Mild steel (b) Cast steel (c) Copper (d) Brass
Ans: B
50. Which of the following are discrete products ?
(a) Nut (b) Bolt (c) Screw (d) All of these
Ans: D
51. Which of the following are continuous products ?
(a) Sheets (metallic) (b) Pipes (c) Wire rolls (d) All of these
Ans: D
52. Babcock & Wilcox boiler is
(a) water tube type (b) fire tube type (c) both (a) and (b) (d) None of these
Ans: A
53. Range of high pressure boilers are
(a) below 80 bar (b) above 80 bar (c) 40 to 80 bar (d) 60 to 80 bar
Ans: B
54. Dry ice is
(a) free from water (b) free from dissolved air or gases
(c) does not contain impurities (d) solidified form of carbon dioxide
Ans: D
55. A simple pitot tube is used to measure
(a) pressure in a static fluid (b) velocity in a flowing stream
(c) total pressure (d) dynamic pressure
Ans: B
56. In magneto ignition system, as the engine speed increases, the value of current
(a) increases (b) decreases (c) remains the same (d) may increase or decrease
Ans: A
57. If the temperature of intake air in an I.C. engine is lowered, its efficiency will
(a) increase (b) decrease (c) remains unchanged (d) will increase upto certain limit and then decrease
Ans: A
58. In a gas turbine cycle with regeneration
(a) pressure ratio increases (b) work output decreases (c) thermal efficiency increases (d) heat input increases
Ans: C
59. The term ‘priming’ in boiler is associated with
(a) removal of air from the boiler shell (b) water particles being carried by steam (c) firing of boiler (d) control of rate of fuel consumption
Ans: B
60. Compression ratio in I.C. engine is defined as the ratio of
(a) total cylinder volume to swept volume (b) total cylinder volume to clearance volume
(c) swept volume to clearance volume (d) None of the above
Ans: B
61. Higher octane rating for S.I. engine fuel indicates that it has
(a) higher calorific value (b) higher volatility (c) higher ignition lag (d) lower ignition lag
Ans: C
62. Boiler mountings are necessary for
(a) operation and safety of a boiler (b) increase the efficiency of boiler (c) both (a) and (b) (d) None of these Ans: A
63. Most important property of I.C. engine lubricant is
(a) density (b) viscosity (c) thermal conductivity (d) None of these
Ans: B
64. The throttling operation in a domestic refrigerator is carried out in
(a) evaporator (b) capillary tube (c) expansion valve (d) condenser
Ans: B
65. Household refrigerators operate on
(a) reversed Carnot cycle (b) cascade refrigeration cycle (c) vapour absorption cycle (d) vapour compression cycle
Ans: D
66. When water – Lithium Bromide is used in a vapour absorption refrigeration system, then
(a) they together act as refrigerant. (b) water is the refrigerant.
(c) lithium bromide is refrigerant. (d) None of these
Ans: B
67. For saturated air, the dew point temperature is
(a) equal to WBT (b) less than WBT (c) more than WBT (d) None of these
Ans: A
68. Process of sensible heating
(a) increases specific humidity (b) decreases specific humidity
(c) decreases relative humidity (d) increases relative humidity
Ans: C
69. Psychrometer is a device which is used to measure
(a) dry bulb temperature (b) wet bulb temperature (c) dry bulb and wet bulb temperature simultaneously (d) dew-point
Ans: C
70. In vapour absorption refrigeration, heat is rejected in
(a) condenser only (b) generator only (c) absorber only (d) both condenser and absorber
Ans: D
71. A heat pump working on a reversed Carnot cycle has a CoP of 4. It is made to work as refrigerator with 1 kW work input. The refrigerating effect will be
(a) 1 (b) 2 (c) 3 (d) 4
Ans: C
72. In conventional refrigerants, which element is responsible for ozone depletion ?
(a) Chlorine (b) Carbon (c) Hydrogen (d) Fluorine
Ans: A
73. Bernoulli’s equation refers to conservation of
(a) mass (b) energy (c) momentum (d) None of these
Ans: B
74. Falling drops of water become spherical in shape due to the property of
(a) adhesion (b) cohesion (c) surface tension (d) viscosity
Ans: C
75. For Parson’s reaction steam turbine, degree of reaction is
(a) 75% (b) 100% (c) 50% (d) 60% Ans: C
76. The velocity of liquid flowing through the divergent portion of a venturimeter
(a) increases (b) decreases (c) remains constant (d) cannot be predicted
Ans: B
77. The shear stress at a point 5 cm from the pipe axis is 20 Pa. The value of shear stress at the pipe wall, having diameter 20 cm will be
(a) 40 Pa (b) 80 Pa (c) 50 Pa (d) cannot be determined
Ans: A
78. Steam turbines are governed by the following methods :
(a) Throttle governing (b) Nozzle control governing (c) By-pass governing (d) All of these Ans: D
79. Which of the following turbine does not require draft tube ?
(a) Kaplan turbine (b) Pelton turbine (c) Francis turbine (d) Propeller turbine
Ans: B
80. The vanes of centrifugal pumps are usually
(a) curved forward (b) curved backward (c) radial (d) None of these
Ans: B
81. Notch is a device used for the measurement of
(a) rate of flow through pipes (b) rate of flow through small channel (c) velocity through pipes (d) velocity through small channels
Ans: B
82. In centrifugal pump, the liquid enters
(a) at the centre (b) at the bottom (c) at the top (d) from sides
Ans: A
83. Francis turbine is used when the available head of water range in
(a) 0 – 25 m (b) 60 – 250 m (c) above 250 m (d) can be used for any head
Ans: B
84. Copper sheets are manufactured by process of
(a) drawing (b) rolling (c) extruding (d) hammering
Ans: B
85. Dies for wire drawing are made of the following material :
(a) cast iron (b) wrought iron (c) mild steel (d) carbides
Ans: D
86. The type of welding used for car bodies is
(a) resistance welding (b) gas welding (c) arc welding (d) None of these
Ans: A
87. Commonly used flame in gas welding is
(a) neutral (b) oxidising (c) carburising (d) None of these
Ans: A
88. Which of the following sands is used to keep away the green sand from sticking to the pattern ?
(a) Core sand (b) Parting sand (c) Loam sand (d) Synthetic sand
Ans: B
89. Sprue in casting refers to
(a) gate (b) runner (c) riser (d) vertical passage
Ans: D
90. The main function of cutting fluid is to
(a) wash away the chips (b) provide lubrication (c) cool the tool and workpiece (d) All of these
Ans: C
91. In which of the following operation on lathe, spindle speed is minimum ?
(a) Knurling (b) Taper turning (c) Fine finishing (d) Thread cutting
Ans: D
92. The size of shaper is specified by
(a) length of stroke (b) size of tool (c) ratio of forward to return stroke (d) size of table
Ans: A
93. Enlarging of an existing circular hole with a rotating single point tool is called
(a) boring (b) drilling (c) reaming (d) internal turning
Ans: A
94. Which of the following material is used as binding material for grinding wheels ?
(a) Silicon carbide (b) Sodium silicate (c) Boron carbide (d) Aluminium oxide
Ans: B
95. The cutting edges of a standard twist drill are called
(a) cutting lip (b) flanks (c) flutes (d) wedges
Ans: A
96. Which of the following is the natural abrasive ?
(a) Al2O3 (b) SiC (c) Boron carbide (d) Corundum
Ans: D
97. For which material, the cutting speed will be minimum for machining ?
(a) Aluminium (b) Brass (c) Copper (d) Cast iron
Ans: D
98. The purpose of using flux in soldering is to
(a) increase fluidity of solder metal (b) prevent oxides formation
(c) wash away the surplus solder (d) lowering the melting temperature of solder
Ans: B
99. In sand moulding, the middle part of flask is called
(a) cope (b) drag (c) cheek (d) middle flask
Ans: C
100. Least shrinkage allowance is provided for the following :
(a) brass (b) aluminium (c) cast iron (d) lead
Ans: C
(a) Sheets (metallic) (b) Pipes (c) Wire rolls (d) All of these
Ans: D
52. Babcock & Wilcox boiler is
(a) water tube type (b) fire tube type (c) both (a) and (b) (d) None of these
Ans: A
53. Range of high pressure boilers are
(a) below 80 bar (b) above 80 bar (c) 40 to 80 bar (d) 60 to 80 bar
Ans: B
54. Dry ice is
(a) free from water (b) free from dissolved air or gases
(c) does not contain impurities (d) solidified form of carbon dioxide
Ans: D
55. A simple pitot tube is used to measure
(a) pressure in a static fluid (b) velocity in a flowing stream
(c) total pressure (d) dynamic pressure
Ans: B
56. In magneto ignition system, as the engine speed increases, the value of current
(a) increases (b) decreases (c) remains the same (d) may increase or decrease
Ans: A
57. If the temperature of intake air in an I.C. engine is lowered, its efficiency will
(a) increase (b) decrease (c) remains unchanged (d) will increase upto certain limit and then decrease
Ans: A
58. In a gas turbine cycle with regeneration
(a) pressure ratio increases (b) work output decreases (c) thermal efficiency increases (d) heat input increases
Ans: C
59. The term ‘priming’ in boiler is associated with
(a) removal of air from the boiler shell (b) water particles being carried by steam (c) firing of boiler (d) control of rate of fuel consumption
Ans: B
60. Compression ratio in I.C. engine is defined as the ratio of
(a) total cylinder volume to swept volume (b) total cylinder volume to clearance volume
(c) swept volume to clearance volume (d) None of the above
Ans: B
61. Higher octane rating for S.I. engine fuel indicates that it has
(a) higher calorific value (b) higher volatility (c) higher ignition lag (d) lower ignition lag
Ans: C
62. Boiler mountings are necessary for
(a) operation and safety of a boiler (b) increase the efficiency of boiler (c) both (a) and (b) (d) None of these Ans: A
63. Most important property of I.C. engine lubricant is
(a) density (b) viscosity (c) thermal conductivity (d) None of these
Ans: B
64. The throttling operation in a domestic refrigerator is carried out in
(a) evaporator (b) capillary tube (c) expansion valve (d) condenser
Ans: B
65. Household refrigerators operate on
(a) reversed Carnot cycle (b) cascade refrigeration cycle (c) vapour absorption cycle (d) vapour compression cycle
Ans: D
66. When water – Lithium Bromide is used in a vapour absorption refrigeration system, then
(a) they together act as refrigerant. (b) water is the refrigerant.
(c) lithium bromide is refrigerant. (d) None of these
Ans: B
67. For saturated air, the dew point temperature is
(a) equal to WBT (b) less than WBT (c) more than WBT (d) None of these
Ans: A
68. Process of sensible heating
(a) increases specific humidity (b) decreases specific humidity
(c) decreases relative humidity (d) increases relative humidity
Ans: C
69. Psychrometer is a device which is used to measure
(a) dry bulb temperature (b) wet bulb temperature (c) dry bulb and wet bulb temperature simultaneously (d) dew-point
Ans: C
70. In vapour absorption refrigeration, heat is rejected in
(a) condenser only (b) generator only (c) absorber only (d) both condenser and absorber
Ans: D
71. A heat pump working on a reversed Carnot cycle has a CoP of 4. It is made to work as refrigerator with 1 kW work input. The refrigerating effect will be
(a) 1 (b) 2 (c) 3 (d) 4
Ans: C
72. In conventional refrigerants, which element is responsible for ozone depletion ?
(a) Chlorine (b) Carbon (c) Hydrogen (d) Fluorine
Ans: A
73. Bernoulli’s equation refers to conservation of
(a) mass (b) energy (c) momentum (d) None of these
Ans: B
74. Falling drops of water become spherical in shape due to the property of
(a) adhesion (b) cohesion (c) surface tension (d) viscosity
Ans: C
75. For Parson’s reaction steam turbine, degree of reaction is
(a) 75% (b) 100% (c) 50% (d) 60% Ans: C
76. The velocity of liquid flowing through the divergent portion of a venturimeter
(a) increases (b) decreases (c) remains constant (d) cannot be predicted
Ans: B
77. The shear stress at a point 5 cm from the pipe axis is 20 Pa. The value of shear stress at the pipe wall, having diameter 20 cm will be
(a) 40 Pa (b) 80 Pa (c) 50 Pa (d) cannot be determined
Ans: A
78. Steam turbines are governed by the following methods :
(a) Throttle governing (b) Nozzle control governing (c) By-pass governing (d) All of these Ans: D
79. Which of the following turbine does not require draft tube ?
(a) Kaplan turbine (b) Pelton turbine (c) Francis turbine (d) Propeller turbine
Ans: B
80. The vanes of centrifugal pumps are usually
(a) curved forward (b) curved backward (c) radial (d) None of these
Ans: B
81. Notch is a device used for the measurement of
(a) rate of flow through pipes (b) rate of flow through small channel (c) velocity through pipes (d) velocity through small channels
Ans: B
82. In centrifugal pump, the liquid enters
(a) at the centre (b) at the bottom (c) at the top (d) from sides
Ans: A
83. Francis turbine is used when the available head of water range in
(a) 0 – 25 m (b) 60 – 250 m (c) above 250 m (d) can be used for any head
Ans: B
84. Copper sheets are manufactured by process of
(a) drawing (b) rolling (c) extruding (d) hammering
Ans: B
85. Dies for wire drawing are made of the following material :
(a) cast iron (b) wrought iron (c) mild steel (d) carbides
Ans: D
86. The type of welding used for car bodies is
(a) resistance welding (b) gas welding (c) arc welding (d) None of these
Ans: A
87. Commonly used flame in gas welding is
(a) neutral (b) oxidising (c) carburising (d) None of these
Ans: A
88. Which of the following sands is used to keep away the green sand from sticking to the pattern ?
(a) Core sand (b) Parting sand (c) Loam sand (d) Synthetic sand
Ans: B
89. Sprue in casting refers to
(a) gate (b) runner (c) riser (d) vertical passage
Ans: D
90. The main function of cutting fluid is to
(a) wash away the chips (b) provide lubrication (c) cool the tool and workpiece (d) All of these
Ans: C
91. In which of the following operation on lathe, spindle speed is minimum ?
(a) Knurling (b) Taper turning (c) Fine finishing (d) Thread cutting
Ans: D
92. The size of shaper is specified by
(a) length of stroke (b) size of tool (c) ratio of forward to return stroke (d) size of table
Ans: A
93. Enlarging of an existing circular hole with a rotating single point tool is called
(a) boring (b) drilling (c) reaming (d) internal turning
Ans: A
94. Which of the following material is used as binding material for grinding wheels ?
(a) Silicon carbide (b) Sodium silicate (c) Boron carbide (d) Aluminium oxide
Ans: B
95. The cutting edges of a standard twist drill are called
(a) cutting lip (b) flanks (c) flutes (d) wedges
Ans: A
96. Which of the following is the natural abrasive ?
(a) Al2O3 (b) SiC (c) Boron carbide (d) Corundum
Ans: D
97. For which material, the cutting speed will be minimum for machining ?
(a) Aluminium (b) Brass (c) Copper (d) Cast iron
Ans: D
98. The purpose of using flux in soldering is to
(a) increase fluidity of solder metal (b) prevent oxides formation
(c) wash away the surplus solder (d) lowering the melting temperature of solder
Ans: B
99. In sand moulding, the middle part of flask is called
(a) cope (b) drag (c) cheek (d) middle flask
Ans: C
100. Least shrinkage allowance is provided for the following :
(a) brass (b) aluminium (c) cast iron (d) lead
Ans: C
· UPSC Exam Syllabus- Mechanical Engineering
· Mechanical Engineering
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