Full-Length Mock Test 5 — RRB JE CBT 2 Technical Abilities Pattern (100 MCQs)

Section A: Engineering Mechanics and Strength of Materials (20 Questions)

1. The unit of force in the SI system is the:
   (a) Newton (b) Joule (c) Watt (d) Pascal
2. The unit of work/energy in the SI system is the:
   (a) Joule (b) Newton (c) Watt (d) Pascal
3. The unit of power in the SI system is the:
   (a) Watt (b) Joule (c) Newton (d) Pascal
4. The unit of stress/pressure in the SI system is the:
   (a) Pascal (b) Newton (c) Joule (d) Watt
5. A rigid body in equilibrium under a system of coplanar forces must satisfy:
   (a) Sum of forces = 0 and sum of moments = 0 (b) Only sum of forces = 0, with no moment condition (c) Only sum of moments = 0, with no force condition (d) Neither condition, as equilibrium requires only constant velocity
6. The coefficient of restitution for a perfectly elastic impact is:
   (a) 1 (b) 0 (c) 0.5 (d) Infinity
7. The coefficient of restitution for a perfectly plastic (inelastic) impact is:
   (a) 0 (b) 1 (c) 0.5 (d) Infinity
8. Work done by a force is defined as the product of force and:
   (a) Displacement in the direction of the force (b) Time for which it acts (c) Mass of the body (d) Velocity of the body squared
9. Kinetic energy of a moving body is given by:
   (a) ½mv² (b) mgh (c) mv (d) F×d only, with no velocity term
10. Potential energy due to gravity is given by:
    (a) mgh (b) ½mv² (c) mv (d) ½kx²
11. The principle of conservation of energy states that energy can neither be created nor destroyed, but can only be:
    (a) Converted from one form to another (b) Increased indefinitely with no limit (c) Decreased to exactly zero in every process (d) Converted only into heat, with no other form possible
12. A shear force diagram shows the variation of shear force along the:
    (a) Length of the beam (b) Height of the cross-section only (c) Width of the cross-section only (d) Time axis, not the beam's length
13. The maximum bending moment in a simply supported beam carrying a single central point load W over span L is:
    (a) WL/4 (b) WL/2 (c) WL (d) WL/8
14. The maximum bending moment in a simply supported beam carrying a uniformly distributed load w over span L is:
    (a) wL²/8 (b) wL²/4 (c) wL²/2 (d) wL/8
15. A cantilever beam of length L carrying a point load W at its free end has a maximum bending moment (at the fixed end) of:
    (a) WL (b) WL/2 (c) WL/4 (d) WL/8
16. The direct (normal) stress in a member under axial load is calculated as:
    (a) Load divided by cross-sectional area (b) Load multiplied by length (c) Load divided by length (d) Load multiplied by area
17. A member subjected to pure shear develops maximum normal stress on planes oriented at:
    (a) 45° to the shear planes (b) Exactly parallel to the shear planes (c) Exactly perpendicular to the shear planes only, with no other consideration (d) 90° to the shear force direction only, with no angle consideration
18. The relationship between the three elastic constants (E, G, and Poisson's ratio μ) for an isotropic material is given by:
    (a) E = 2G(1+μ) (b) E = G(1−μ) (c) E = G/μ (d) E = Gμ²
19. Thermal stress develops in a restrained member when its temperature changes and it is prevented from:
    (a) Freely expanding or contracting (b) Rotating about its own axis (c) Changing colour (d) Conducting electricity
20. A solid circular shaft transmitting torque T has maximum shear stress at the outer surface given by a formula involving T and the shaft's:
    (a) Polar moment of inertia and outer radius (b) Young's modulus only, with no radius term (c) Length only, with no radius or polar moment term (d) Density only

Section B: Thermodynamics, IC Engines, and Power Plant Engineering (20 Questions)

21. The First Law of Thermodynamics applied to a closed system is expressed as change in internal energy equals:
    (a) Heat added minus work done by the system (b) Work done minus heat added (c) Heat added multiplied by work done (d) Zero, always, regardless of heat or work
22. An ideal gas obeys the equation of state:
    (a) pV = mRT (b) p + V = RT (c) p/V = RT (d) pVT = R
23. The specific gas constant R for an ideal gas is related to the universal gas constant Ru and molar mass M by:
    (a) R = Ru/M (b) R = Ru × M (c) R = Ru + M (d) R = Ru − M
24. A polytropic process follows the relation:
    (a) pVⁿ = constant, for some index n (b) p = constant only, with no volume relation (c) V = constant only, with no pressure relation (d) T = constant only, with no pressure or volume relation
25. For an isothermal process of an ideal gas, the polytropic index n equals:
    (a) 1 (b) 0 (c) γ (the ratio of specific heats) (d) Infinity
26. For an adiabatic (isentropic) process of an ideal gas, the polytropic index n equals:
    (a) γ (the ratio of specific heats) (b) 1 (c) 0 (d) Infinity
27. A throttling process (such as flow through a partially open valve) is characterised by:
    (a) Constant enthalpy, with no useful work done (b) Constant entropy with significant useful work extracted (c) Constant volume with no pressure drop (d) Constant temperature with no enthalpy change possible
28. The Clausius statement of the Second Law of Thermodynamics asserts that heat cannot spontaneously flow from a:
    (a) Colder body to a hotter body, without external work input (b) Hotter body to a colder body under any condition (c) System to its surroundings under any condition (d) Solid to a liquid under any condition
29. An air-standard cycle analysis of IC engines assumes the working fluid behaves as:
    (a) An ideal gas (air) throughout the cycle (b) A pure liquid throughout the cycle (c) A solid throughout the cycle (d) A vacuum with no working fluid present
30. The dual cycle (mixed cycle) combines heat addition partly at constant volume and partly at constant:
    (a) Pressure (b) Temperature (c) Entropy (d) Density
31. Mean effective pressure (MEP) of an engine cycle is a hypothetical constant pressure that, acting through the piston's stroke, would produce:
    (a) The same net work as the actual cycle (b) Zero net work under all conditions (c) Infinite work regardless of stroke (d) Only negative work
32. Brake power of an engine is the power measured at the:
    (a) Output shaft (crankshaft), after accounting for friction losses (b) Indicator diagram only, before any friction loss (c) Fuel pump only, with no relation to the shaft (d) Cooling system only, with no relation to the shaft
33. Indicated power of an engine is the power developed:
    (a) Inside the cylinder, based on the indicator diagram, before friction losses (b) At the output shaft only, after all losses (c) By the cooling system exclusively (d) By the fuel injection pump exclusively
34. Mechanical efficiency of an engine is defined as the ratio of:
    (a) Brake power to indicated power (b) Indicated power to brake power (c) Thermal efficiency to volumetric efficiency (d) Fuel consumption to air consumption
35. A boiler's efficiency is defined as the ratio of heat used in generating steam to the:
    (a) Heat supplied by the fuel burned (b) Heat rejected in the exhaust gases only (c) Total boiler surface area (d) Total steam pressure
36. Feedwater treatment in a boiler system is important primarily to prevent:
    (a) Scale formation and corrosion within the boiler (b) Increase in boiler pressure beyond the design limit deliberately (c) Combustion of the fuel entirely (d) Condensation of steam in the turbine
37. Draught in a boiler furnace refers to the:
    (a) Pressure difference that causes air/flue gas flow through the furnace and chimney (b) Total volume of the furnace (c) Colour of the flame (d) Type of fuel used exclusively
38. A superheater in a boiler system is used to:
    (a) Raise the temperature of saturated steam above its saturation temperature (b) Cool the steam back into water (c) Compress the steam to a higher pressure (d) Filter impurities from the feedwater
39. An economiser in a boiler system is used to:
    (a) Preheat the feedwater using waste heat from flue gases (b) Generate the initial steam directly, replacing the boiler drum (c) Cool the flue gases to below ambient temperature for disposal (d) Increase the fuel's calorific value chemically
40. Solar photovoltaic power generation converts solar energy directly into:
    (a) Electrical energy, via the photovoltaic effect (b) Mechanical energy directly, with no electrical intermediate step (c) Thermal energy exclusively, with no electrical output (d) Nuclear energy

Section C: Theory of Machines and Machine Design (20 Questions)

41. A kinematic chain becomes a mechanism when one of its links is:
    (a) Fixed (b) Removed entirely (c) Made flexible rather than rigid (d) Replaced by a fluid coupling
42. The number of degrees of freedom of a planar mechanism with l links and j lower pairs and no higher pairs is commonly given by:
    (a) 3(l−1) − 2j (b) 3l + 2j (c) l − j (d) l + j
43. A cam with a roller follower, compared to a knife-edge follower, generally provides:
    (a) Reduced wear due to rolling rather than sliding contact (b) Increased wear compared to a knife-edge follower in every case (c) No difference in wear whatsoever (d) Function only in stationary (non-cam) applications
44. In gear terminology, "backlash" refers to the:
    (a) Small clearance between mating gear teeth to allow for lubrication and thermal expansion (b) Total number of teeth on the gear (c) Angle of the gear's helix (d) Exact pitch circle diameter of the gear
45. A rack and pinion mechanism converts:
    (a) Rotary motion of the pinion into linear motion of the rack (or vice versa) (b) Only linear motion into linear motion of equal magnitude (c) Only rotary motion into rotary motion at a fixed 1:1 ratio (d) Electrical energy directly into mechanical energy with no motion conversion
46. The "law of gearing" requires that the common normal at the point of contact between mating teeth must always:
    (a) Pass through the pitch point (b) Be tangent to both pitch circles simultaneously (c) Be perpendicular to both gear axes (d) Coincide with the line of centres at all points of contact
47. Involute gear tooth profiles are generated as the locus of a point on a:
    (a) Taut string unwound from a base circle (b) Cycloid rolling on a straight line (c) Random curve with no defined generation method (d) Straight line passing through the gear's centre only
48. The primary advantage of the involute gear tooth profile over the cycloidal profile is its tolerance to small variations in:
    (a) Centre distance between the meshing gears (b) Gear material only, with no relation to centre distance (c) Ambient temperature exclusively (d) Lubricant viscosity exclusively
49. A worm and worm wheel arrangement, compared to a simple spur gear pair, provides:
    (a) A much higher speed reduction ratio in a compact arrangement (b) Only a 1:1 ratio, identical to spur gears (c) Speed increase only, never reduction (d) No load-carrying capacity at all
50. The self-locking property of certain worm gear sets means that:
    (a) The worm wheel cannot drive the worm backward under normal conditions (b) The worm gear set cannot transmit any torque at all (c) The worm and worm wheel are permanently welded together (d) The gear set operates only at zero speed
51. A belt drive transmits power between two shafts using:
    (a) Friction between the belt and the pulleys (b) Direct meshing of gear teeth (c) A rigid, non-flexible connecting rod (d) Hydraulic fluid pressure exclusively
52. Slip in a belt drive refers to the:
    (a) Relative motion between the belt and pulley surface, reducing the theoretical velocity ratio (b) Complete separation of the belt from both pulleys (c) Exact 1:1 velocity ratio maintained at all times with no deviation (d) Colour fading of the belt material over time
53. A chain drive, compared to a belt drive, generally offers:
    (a) A positive (no-slip) drive due to the meshing of chain links with sprocket teeth (b) A drive that always slips significantly, more than a belt (c) No possibility of transmitting torque at all (d) Function only at extremely low torque levels, with no other capability
54. The design of a key for connecting a gear to a shaft considers failure by shearing along the key's:
    (a) Length, at the shaft-hub interface (b) Width only, with no length consideration (c) Colour only, with no dimensional consideration (d) Manufacturing date only
55. A shrink fit (interference fit) assembly is achieved by:
    (a) Heating the outer member (or cooling the inner member) before assembly (b) Machining both members to exactly the same size with zero tolerance in every case (c) Using only adhesive bonding, with no thermal or mechanical means (d) Welding the two members together permanently before any fit is considered
56. The endurance limit of a material, relevant to fatigue design, is most closely associated with the:
    (a) S-N curve (stress amplitude vs. number of cycles to failure) (b) Stress-strain curve under static loading only (c) Pressure-volume diagram of a gas (d) Temperature-entropy diagram of steam
57. A fillet radius provided at a sudden change of cross-section in a machine component primarily serves to:
    (a) Reduce stress concentration at that location (b) Increase stress concentration deliberately for testing purposes (c) Serve only a decorative/aesthetic function (d) Increase the component's overall weight with no stress-related benefit
58. The design of a helical compression spring considers wire diameter, coil diameter, and:
    (a) Number of active coils (b) Colour of the wire only (c) Manufacturer's brand name only (d) Ambient humidity only, with no other design parameter
59. A deep groove ball bearing is described as versatile because it can carry:
    (a) Combined radial and moderate axial load (b) Only pure axial load, with no radial capacity at all (c) Only pure radial load, with no axial capacity at all (d) No load of any kind, serving only a guiding function
60. Rolling contact bearing life (L10) is inversely related to a power of the applied:
    (a) Load (b) Ambient temperature only (c) Lubricant colour only (d) Bearing's manufacturing date only

Section D: Fluid Mechanics, Manufacturing, Metrology, Heat Transfer, and Material Science (20 Questions)

61. The hydrostatic pressure at a depth h in a static fluid of density ρ is given by:
    (a) ρgh (b) ρg/h (c) ρ/(gh) (d) gh/ρ
62. A manometer is an instrument used to measure:
    (a) Pressure, using a column of liquid (b) Only temperature, with no relation to pressure (c) Only flow velocity directly, with no pressure relation (d) Only viscosity directly
63. The specific weight of a fluid is defined as its weight per unit:
    (a) Volume (b) Mass (c) Area (d) Length
64. A centrifugal compressor, similar in principle to a centrifugal pump, is used to compress:
    (a) Gases (typically air) rather than liquids (b) Only liquids, never gases (c) Only solids, with no fluid involved at all (d) Only vacuum, with no actual fluid present
65. Net Positive Suction Head (NPSH) is a parameter important in centrifugal pump selection primarily to avoid:
    (a) Cavitation at the pump suction (b) Excessive discharge pressure only, with no suction-side concern (c) Excessive pump speed only, with no pressure-related concern (d) Excessive pump weight only, with no hydraulic concern
66. Welding processes that use a consumable electrode, which melts and becomes part of the weld, include:
    (a) Shielded metal arc welding (SMAW) (b) Tungsten inert gas (TIG) welding exclusively, which never uses a consumable electrode (c) Only laser welding, with no arc-based process involved (d) Only ultrasonic welding, with no melting involved
67. Brazing and soldering, unlike fusion welding, join metals:
    (a) Without melting the base metal itself, using a lower-melting-point filler material (b) By melting and fusing the base metals directly together, identical to arc welding (c) Using no filler material of any kind (d) Only at temperatures above the base metal's melting point
68. Powder metallurgy is a manufacturing process that produces components by:
    (a) Compacting and sintering metal powders (b) Melting and casting molten metal into a mould (c) Removing material via machining from a solid block (d) Joining pre-formed parts using an electric arc
69. Non-destructive testing (NDT) methods, such as ultrasonic testing and radiography, are used to detect:
    (a) Internal/surface defects without damaging the component (b) Only surface colour variations, with no relation to defects (c) Only the component's exact weight (d) Only the component's electrical conductivity
70. A limit gauge (such as a plug or ring gauge) is used to quickly check whether a dimension:
    (a) Falls within the specified tolerance limits (b) Exactly matches a single, absolute numerical value with infinite precision (c) Has any colour variation (d) Has any electrical conductivity variation
71. A profilometer is used to measure:
    (a) Surface roughness (b) Only bulk material hardness (c) Only internal material composition (d) Only overall component weight
72. Latent heat is the heat absorbed or released during a:
    (a) Phase change, at constant temperature (b) Temperature rise with no phase change (c) Purely mechanical process with no thermal effect (d) Chemical reaction only, with no relation to phase change
73. Specific heat capacity of a substance is the heat required to raise the temperature of a unit mass by:
    (a) One degree (b) Ten degrees (c) A phase change temperature only (d) Zero degrees
74. In a vapour compression cycle, refrigerants such as R-134a have replaced older CFCs primarily due to concerns over:
    (a) Ozone depletion (and, more recently, global warming potential) (b) Excessive cost of production only, with no environmental concern (c) Complete absence of any refrigerating effect (d) Incompatibility with any compressor design
75. A hexagonal close-packed (HCP) crystal structure, found in metals like magnesium, generally gives:
    (a) Lower ductility due to fewer available slip systems (b) The highest ductility of all crystal structures, exceeding FCC (c) No crystalline structure at all (d) Only amorphous (non-crystalline) behaviour
76. Normalising of steel, compared to annealing, involves cooling in:
    (a) Still air, rather than in the furnace (b) Water, exactly like quenching for hardening (c) Oil, exactly like quenching for hardening (d) A vacuum chamber only, with no other medium
77. Copper-tin alloys are commonly known as:
    (a) Bronze (b) Brass (c) Steel (d) Cast iron
78. A composite material combines a reinforcement embedded in a:
    (a) Matrix material (b) Pure vacuum, with no matrix at all (c) Molten metal bath only, with no solid matrix (d) Gas phase only, with no solid or liquid matrix
79. The three-wire method in metrology is used to measure the:
    (a) Effective (pitch) diameter of a screw thread (b) Overall length of a shaft only (c) Surface roughness of a bearing bore (d) Hardness of a gear tooth
80. An autocollimator is an optical instrument used to measure small:
    (a) Angular deviations (b) Only linear lengths, with no angular capability (c) Only material hardness values (d) Only fluid pressure values

Section E: General Awareness, Computer Applications, and Current Affairs (20 Questions)

81. The Central Board of Irrigation and Power (CBIP) is primarily concerned with:
    (a) Technical development in power and water resources sectors (b) Railway safety standards exclusively (c) Currency and banking regulation (d) Postal service standards
82. The Council of Scientific and Industrial Research (CSIR) in India functions under which broad area?
    (a) Scientific and industrial research (b) Railway ticketing exclusively (c) Currency printing exclusively (d) Postal service exclusively
83. In computing, "CPU" stands for:
    (a) Central Processing Unit (b) Central Program Utility (c) Computer Peripheral Unit (d) Central Power Unit
84. A "spreadsheet" application, such as MS Excel, is primarily used for:
    (a) Organizing, calculating, and analysing data in rows and columns (b) Only playing audio/video files (c) Only sending emails (d) Only browsing the internet
85. The full form of "HTTP" is:
    (a) HyperText Transfer Protocol (b) High Transmission Text Protocol (c) Home Terminal Transfer Program (d) Hyperlink Text Transmission Path
86. A "database management system" (DBMS) is software used to:
    (a) Store, organize, and retrieve structured data efficiently (b) Only display static images with no data storage (c) Only play music files (d) Only manage printer queues
87. India's National Education Policy (NEP) emphasises, among other goals, greater focus on:
    (a) Vocational education and skill integration (b) Elimination of all vocational training (c) Only rote memorisation with no skill focus (d) Only foreign language instruction with no domestic curriculum focus
88. The Indian Institutes of Technology (IITs) are premier institutions primarily focused on:
    (a) Engineering, technology, and applied sciences education (b) Only agricultural extension services (c) Only postal service training (d) Only currency printing operations
89. The Council for Scientific and Industrial Research's National Physical Laboratory (NPL) in India serves as the national custodian of:
    (a) Measurement standards (metrology) (b) Railway safety certificates only (c) Postal stamps only (d) Currency notes only
90. National Institutes of Technology (NITs) in India are premier institutions offering:
    (a) Technical/engineering education across various states (b) Only medical education, with no engineering focus (c) Only management education, with no technical focus (d) Only law education, with no technical focus
91. Engineering Services Examination (ESE), conducted by the Union Public Service Commission, recruits engineers for:
    (a) Various government engineering services (b) Only private-sector companies exclusively (c) Only foreign government services (d) Only local municipal sanitation departments exclusively
92. The National Design Institute framework in India supports:
    (a) Design innovation across engineering and product sectors (b) Only textile pattern design, with no engineering relevance (c) Only currency design (d) Only postal stamp design
93. Automation in Indian manufacturing is increasingly supported through schemes promoting:
    (a) Adoption of robotics, IoT, and digital manufacturing technologies (b) Complete rejection of any automation or digital technology (c) Only manual, non-mechanised production methods (d) Only agricultural machinery, with no factory relevance
94. The "Startup India" initiative aims to:
    (a) Foster entrepreneurship and innovation-driven startups (b) Discourage new business formation (c) Apply only to established large corporations (d) Eliminate the need for any regulatory framework
95. Engineering colleges in India are commonly accredited by bodies such as the:
    (a) National Board of Accreditation (NBA) (b) Reserve Bank of India exclusively (c) Election Commission of India exclusively (d) Central Board of Film Certification exclusively
96. Renewable energy capacity addition in India has particularly emphasised growth in:
    (a) Solar and wind power (b) Only coal-based thermal power (c) Only nuclear power exclusively (d) Only imported fossil fuels
97. The "Digital Locker" (DigiLocker) initiative in India allows citizens to:
    (a) Store and access official documents digitally (b) Only make railway ticket bookings (c) Only pay electricity bills (d) Only access postal tracking information
98. Robotics Process Automation (RPA), increasingly used in industry, primarily automates:
    (a) Repetitive, rule-based digital/administrative tasks (b) Only heavy manual labour with no digital component (c) Only agricultural harvesting (d) Only mining operations exclusively
99. Engineering apprenticeship and industrial training institutes (ITIs) in India primarily provide:
    (a) Vocational and technical skill training (b) Only university-level research degrees (c) Only postgraduate medical training (d) Only law degrees
100. The term "smart factory," associated with Industry 4.0, refers to a manufacturing facility that uses:
     (a) Interconnected, data-driven automation for adaptive, efficient production (b) Only manual, disconnected machines with no data exchange (c) Only 19th-century steam power with no modern technology (d) Only agricultural equipment, with no manufacturing relevance

Answer Key with Explanations

1.(a) The SI unit of force is the newton.

2.(a) The SI unit of work/energy is the joule.

3.(a) The SI unit of power is the watt.

4.(a) The SI unit of stress/pressure is the pascal.

5.(a) Equilibrium requires sum of forces = 0 and sum of moments = 0.

6.(a) Coefficient of restitution = 1 for perfectly elastic impact.

7.(a) Coefficient of restitution = 0 for perfectly plastic impact.

8.(a) Work = force × displacement in the force's direction.

9.(a) Kinetic energy = ½mv².

10.(a) Gravitational PE = mgh.

11.(a) Energy conservation: energy converts between forms, never created/destroyed.

12.(a) An SFD shows shear force variation along the beam's length.

13.(a) Max BM for central point load = WL/4.

14.(a) Max BM for UDL on simply supported beam = wL²/8.

15.(a) Max BM for a cantilever with end point load = WL.

16.(a) Direct stress = load / cross-sectional area.

17.(a) Pure shear gives maximum normal stress at 45° to shear planes.

18.(a) E = 2G(1+μ) relates the elastic constants.

19.(a) Thermal stress arises when expansion/contraction is restrained.

20.(a) Max torsional shear stress involves polar moment of inertia and outer radius.

21.(a) First Law: ΔU = Q − W (heat added minus work done by system).

22.(a) Ideal gas law: pV = mRT.

23.(a) R = Ru/M.

24.(a) Polytropic process: pVⁿ = constant.

25.(a) Isothermal process has n = 1.

26.(a) Adiabatic process has n = γ.

27.(a) Throttling is a constant-enthalpy process with no useful work.

28.(a) Clausius statement: heat cannot flow spontaneously from cold to hot without work input.

29.(a) Air-standard analysis assumes the working fluid is an ideal gas (air).

30.(a) The dual cycle adds heat partly at constant volume, partly at constant pressure.

31.(a) MEP is the constant pressure giving the same net work as the actual cycle.

32.(a) Brake power is measured at the output shaft, after friction losses.

33.(a) Indicated power is developed inside the cylinder, before friction losses.

34.(a) Mechanical efficiency = brake power / indicated power.

35.(a) Boiler efficiency = heat used for steam / heat supplied by fuel.

36.(a) Feedwater treatment prevents scale formation and corrosion.

37.(a) Draught is the pressure difference driving air/flue gas flow.

38.(a) A superheater raises steam temperature above saturation temperature.

39.(a) An economiser preheats feedwater using flue gas waste heat.

40.(a) Solar PV converts solar energy directly into electrical energy.

41.(a) A kinematic chain becomes a mechanism when a link is fixed.

42.(a) DOF = 3(l−1) − 2j for lower pairs only.

43.(a) Roller followers reduce wear via rolling rather than sliding contact.

44.(a) Backlash is the small clearance between mating gear teeth.

45.(a) A rack and pinion converts rotary motion to linear motion (or vice versa).

46.(a) The law of gearing requires the common normal to pass through the pitch point.

47.(a) Involute profiles are generated by a taut string unwound from a base circle.

48.(a) Involute profiles tolerate small centre distance variations.

49.(a) Worm gearing gives a high, compact speed reduction ratio.

50.(a) Self-locking worm gears prevent the wheel from driving the worm backward.

51.(a) Belt drives transmit power via friction between belt and pulleys.

52.(a) Slip is relative motion between belt and pulley reducing the velocity ratio.

53.(a) Chain drives give a positive, no-slip drive via meshing.

54.(a) Key design considers shear failure along the key's length.

55.(a) A shrink fit is achieved by heating the outer (or cooling the inner) member.

56.(a) The endurance limit relates to the S-N fatigue curve.

57.(a) A fillet radius reduces stress concentration.

58.(a) Helical spring design considers wire/coil diameter and number of active coils.

59.(a) Deep groove ball bearings carry combined radial and moderate axial load.

60.(a) L10 bearing life is inversely related to a power of the applied load.

61.(a) Hydrostatic pressure = ρgh.

62.(a) A manometer measures pressure using a liquid column.

63.(a) Specific weight = weight per unit volume.

64.(a) A centrifugal compressor compresses gases, unlike a pump for liquids.

65.(a) NPSH consideration avoids cavitation at pump suction.

66.(a) SMAW uses a consumable electrode.

67.(a) Brazing/soldering join without melting the base metal, using a lower-melting filler.

68.(a) Powder metallurgy compacts and sinters metal powders.

69.(a) NDT detects defects without damaging the component.

70.(a) Limit gauges check whether a dimension is within tolerance.

71.(a) A profilometer measures surface roughness.

72.(a) Latent heat is absorbed/released during a phase change at constant temperature.

73.(a) Specific heat capacity raises unit mass temperature by one degree.

74.(a) R-134a replaced CFCs due to ozone depletion (and GWP) concerns.

75.(a) HCP gives lower ductility due to fewer slip systems.

76.(a) Normalising cools in still air, unlike furnace-cooled annealing.

77.(a) Copper-tin alloys are bronze.

78.(a) A composite combines reinforcement in a matrix material.

79.(a) The three-wire method measures effective (pitch) diameter of a thread.

80.(a) An autocollimator measures small angular deviations.

81.(a) CBIP deals with technical development in power/water resources.

82.(a) CSIR focuses on scientific and industrial research.

83.(a) CPU stands for Central Processing Unit.

84.(a) A spreadsheet organizes/calculates/analyses data in rows/columns.

85.(a) HTTP stands for HyperText Transfer Protocol.

86.(a) A DBMS stores, organizes, and retrieves structured data.

87.(a) NEP emphasises vocational education and skill integration.

88.(a) IITs focus on engineering, technology, and applied sciences.

89.(a) NPL is the national custodian of measurement standards.

90.(a) NITs offer technical/engineering education across states.

91.(a) ESE recruits engineers for government engineering services.

92.(a) National design institute frameworks support design innovation across sectors.

93.(a) Manufacturing automation schemes promote robotics/IoT/digital tech adoption.

94.(a) Startup India fosters entrepreneurship and innovation-driven startups.

95.(a) Engineering colleges are accredited by the NBA.

96.(a) India's renewable capacity growth emphasises solar and wind.

97.(a) DigiLocker allows digital storage/access of official documents.

98.(a) RPA automates repetitive, rule-based digital/administrative tasks.

99.(a) ITIs provide vocational and technical skill training.

100.(a) A smart factory uses interconnected, data-driven automation.