BARC ST (Mechanical) Mock Test – Part 1

Instructions:

• Total Questions: 100
• Each question carries 1 mark
• Time: 90 minutes for full test
• Negative marking: 0.25 per wrong answer

Parameter	Details
Exam Type	Computer-Based Test (CBT) – Objective Multiple Choice Questions (MCQs)
Total Questions	100
Maximum Marks	100 (1 mark per question)
Duration	90–120 minutes
Sections	4 Sections
Section-wise Distribution	1. Mechanical Engineering Fundamentals – 25 Qs 2. Workshop & Manufacturing Technology – 25 Qs 3. Thermodynamics, Fluid Mechanics & Heat Transfer – 25 Qs 4. Strength of Materials, Engineering Mechanics & Miscellaneous Technical Knowledge – 25 Qs
Question Type	Multiple Choice Questions (MCQs) with 4 options each
Marking Scheme	+1 mark for correct answer, –0.25 for wrong answer
Syllabus Coverage	– Mechanical Engineering Fundamentals (Stress, Strain, Torsion, Bending) – Workshop & Manufacturing Technology (Machining, Welding, Casting, CNC) – Thermodynamics & Heat Transfer (Engines, Boilers, Refrigeration, Fluid Flow) – Strength of Materials & Engineering Mechanics – Basic Mathematics, Numerical Ability, and Reasoning
Purpose	To assess technical knowledge, analytical skills, and problem-solving ability of candidates for Mechanical ST positions at BARC

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Section A – Mechanical Engineering Fundamentals (Q1–25)

Q1. The moment of inertia of a solid circular shaft about its axis is:

A. $\pi d^4 / 64$πd4/64
B. $\pi d^4 / 32$πd4/32
C. $\pi d^3 / 16$πd3/16
D. $\pi d^3 / 32$πd3/32

Q2. In a simply supported beam with uniform load, maximum bending moment occurs at:

A. Supports
B. Mid-span
C. One-third span
D. Quarter span

Q3. Flywheels are used in engines to:

A. Reduce weight
B. Store energy and reduce speed fluctuations
C. Increase torque
D. Improve lubrication

Q4. The efficiency of a machine is given by:

A. Work output / Work input × 100
B. Work input / Work output × 100
C. Output force / Input force
D. None of the above

Q5. The unit of torque in SI system is:

A. N·m
B. J
C. N·m²
D. W

Q6. In a four-stroke IC engine, power stroke occurs during:

A. Intake stroke
B. Compression stroke
C. Power stroke
D. Exhaust stroke

Q7. Which of the following gears is used to transmit motion between non-parallel, non-intersecting shafts?

A. Spur gear
B. Bevel gear
C. Worm gear
D. Helical gear

Q8. The stress in a shaft subjected to torque T is given by:

A. $\tau = T \cdot r / J$τ=T⋅r/J
B. $\tau = T / r$τ=T/r
C. $\tau = J / T$τ=J/T
D. $\tau = T \cdot J / r$τ=T⋅J/r

Q9. In thermodynamics, the first law relates:

A. Heat and work to internal energy
B. Entropy and temperature
C. Pressure and volume
D. Force and displacement

Q10. The critical point of a substance is the point at which:

A. Liquid and vapor coexist at equilibrium
B. Pressure is maximum
C. Temperature is zero
D. Density is zero

Q11. In refrigeration, which component reduces the pressure and temperature of the refrigerant?

A. Compressor
B. Condenser
C. Expansion valve
D. Evaporator

Q12. The efficiency of a Carnot engine depends on:

A. Working substance
B. Temperature difference between heat source and sink
C. Pressure of working fluid
D. Heat input only

Q13. In fluid mechanics, Bernoulli’s principle assumes:

A. Flow is viscous
B. Flow is inviscid and steady
C. Flow is compressible
D. Flow is turbulent

Q14. A cantilever beam with a point load at free end has maximum bending moment at:

A. Free end
B. Mid-span
C. Fixed end
D. Quarter span

Q15. The simple shear stress in a circular shaft is directly proportional to:

A. Torque and radius, inversely proportional to polar moment of inertia
B. Torque only
C. Radius only
D. None of the above

Q16. In welding, which defect occurs due to rapid cooling?

A. Porosity
B. Cracks
C. Slag inclusion
D. Undercut

Q17. Which welding process uses a consumable electrode with shielding gas?

A. SMAW
B. TIG
C. MIG
D. Oxy-acetylene

Q18. Coefficient of friction depends on:

A. Area of contact
B. Normal force
C. Nature of surfaces
D. Both B and C

Q19. High-speed steel is commonly used for:

A. Bearings
B. Cutting tools
C. Springs
D. Gears

Q20. In EDM (Electric Discharge Machining), material is removed by:

A. Mechanical cutting
B. Chemical reaction
C. Electric sparks
D. Abrasive action

Q21. Surface roughness is measured in:

A. Micrometers (µm)
B. Millimeters (mm)
C. Nanometers (nm)
D. Centimeters (cm)

Q22. The main advantage of CNC machines is:

A. High speed only
B. Automation and precision
C. Low cost only
D. Manual control

Q23. Boring is used to:

A. Cut external surfaces
B. Enlarge existing holes with precision
C. Cut threads
D. Grind surfaces

Q24. A lathe dead center is used to:

A. Drive the workpiece
B. Support free end without rotation
C. Rotate with the workpiece
D. Cut threads

Q25. Energy stored in a spring subjected to load is:

A. 1/2 k x²
B. k x²
C. 2 k x²
D. k / x²

Section B – Workshop & Manufacturing Technology (Q26–50)

Q26. Which process removes material by shearing?

A. Milling
B. Turning
C. Drilling
D. Punching

Q27. The process of hardening steel by heating and quenching is called:

A. Annealing
B. Tempering
C. Normalizing
D. Hardening

Q28. In casting, the riser is used to:

A. Reduce turbulence
B. Feed molten metal to shrinkage zones
C. Create mold cavity
D. Support the mold

Q29. In Lathe operation, depth of cut affects:

A. Surface finish only
B. Material removal rate and surface finish
C. Feed only
D. Cutting speed

Q30. A lathe center used to hold workpiece is:

A. Drive center
B. Dead center
C. Live center
D. Rotating center

Q31. Which welding defect is caused by rapid cooling?

A. Porosity
B. Cracks
C. Undercut
D. Slag inclusion

Q32. EDM stands for:

A. Electric Discharge Machining
B. Electrochemical Deposition Method
C. Electro Dynamic Mechanism
D. Electrical Drill Machining

Q33. Which machine is suitable for cutting gears?

A. Lathe
B. Milling machine
C. Shaper
D. Planer

Q34. Surface roughness is measured in:

A. Micrometers (µm)
B. Millimeters (mm)
C. Nanometers (nm)
D. Centimeters (cm)

Q35. Which metal is commonly used for making cutting tools?

A. Mild steel
B. High-speed steel
C. Aluminum
D. Copper

Q36. Which process is used for precision cylindrical holes?

A. Boring
B. Milling
C. Turning
D. Shaping

Q37. The main advantage of CNC machines is:

A. High speed only
B. Automation and precision
C. Low cost
D. Manual control

Q38. Which of the following is a non-traditional machining process?

A. Turning
B. Milling
C. EDM
D. Grinding

Q39. In welding, electrode coating provides:

A. Filler material
B. Slag formation
C. Gas shield
D. All of the above

Q40. Hardness of steel is measured by:

A. Brinell test
B. Rockwell test
C. Vickers test
D. All of the above

Q41. In a grinding operation, the wheel speed is usually measured in:

A. RPM
B. m/s
C. m/min
D. cm/s

Q42. Which of the following is a casting defect?

A. Shrinkage cavity
B. Porosity
C. Cold shut
D. All of the above

Q43. The term “feed” in machining refers to:

A. Depth of cut per pass
B. Distance tool advances per revolution of workpiece
C. Cutting speed
D. Power consumed

Q44. Which of the following is used as a lubricant in machining?

A. Water
B. Oil
C. Graphite
D. All of the above

Q45. A shaper is primarily used for:

A. Cutting internal threads
B. Producing flat surfaces
C. Drilling holes
D. Turning cylindrical work

Q46. The cutting speed in turning operation depends on:

A. Diameter of workpiece
B. RPM of spindle
C. Both diameter and RPM
D. Feed rate only

Q47. In welding, the main function of a filler metal is:

A. Protect weld
B. Fill the joint
C. Reduce heat
D. Improve electrode life

Q48. Which material is commonly used for tool dies?

A. Mild steel
B. High carbon steel
C. HSS
D. Tungsten carbide

Q49. In casting, a core is used to:

A. Reduce shrinkage
B. Produce hollow sections
C. Support mold
D. Increase strength

Q50. Which cutting tool geometry affects surface finish and chip formation?

A. Rake angle
B. Clearance angle
C. Nose radius
D. All of the above

Section C – Thermodynamics, Fluid Mechanics & Heat Transfer (Q51–75)

Q51. Reynolds number is used to determine:

A. Pressure drop
B. Flow type (laminar or turbulent)
C. Fluid density
D. Pipe diameter

Q52. In a nozzle, the velocity of fluid is maximum at:

A. Inlet
B. Throat
C. Exit
D. Mid-length

Q53. Pascal’s law is applied in:

A. Hydraulic systems
B. Thermodynamics
C. Heat exchangers
D. Boilers

Q54. Ideal gas equation is:

A. PV = nRT
B. P + V = nRT
C. P / V = nRT
D. P – V = nRT

Q55. Which of the following is a reversible process?

A. Adiabatic
B. Isothermal
C. Both A and B
D. None

Q56. The efficiency of a Carnot engine is given by:

A. 1 – (T_C / T_H)
B. 1 – (T_H / T_C)
C. W / Q
D. Q / W

Q57. In a heat exchanger, counterflow arrangement:

A. Reduces heat transfer
B. Improves heat transfer efficiency
C. Reduces pressure drop
D. Increases thermal resistance

Q58. Viscosity of a fluid is a measure of:

A. Density
B. Internal resistance to flow
C. Pressure drop
D. Velocity

Q59. In a boiler, the main purpose is to:

A. Heat water
B. Generate steam at desired pressure
C. Reduce temperature
D. Compress air

Q60. Critical point of water is:

A. 100°C and 1 atm
B. 374°C and 22.06 MPa
C. 373°C and 1 atm
D. 200°C and 10 MPa

Q61. A substance changes from vapor to liquid at constant temperature; this process is called:

A. Evaporation
B. Condensation
C. Sublimation
D. Boiling

Q62. The specific heat ratio (γ) of air is approximately:

A. 1.2
B. 1.4
C. 1.6
D. 1.33

Q63. The term “enthalpy” represents:

A. Internal energy + PV
B. PV only
C. Work done
D. Heat lost

Q64. In compressible flow, Mach number > 1 indicates:

A. Subsonic flow
B. Sonic flow
C. Supersonic flow
D. None of the above

Q65. In fluid mechanics, Bernoulli’s equation neglects:

A. Viscous effects
B. Pressure variations
C. Velocity variations
D. Height variations

Q66. Hydraulic machines operate mainly on:

A. Pascal’s law
B. Archimedes principle
C. Bernoulli principle
D. Newton’s second law

Q67. In forced convection, the heat transfer rate depends on:

A. Fluid velocity
B. Fluid properties
C. Surface area
D. All of the above

Q68. In a reciprocating compressor, the compression stroke does:

A. Draw in air
B. Compress air
C. Deliver air to discharge
D. Cool the air

Q69. The efficiency of a heat engine is always less than:

A. 100%
B. 50%
C. 75%
D. 90%

Q70. The Reynolds number formula is:

A. Re = ρVD / μ
B. Re = μ / ρVD
C. Re = VD / μ
D. Re = ρV / D

Q71. Fourier’s law applies to:

A. Fluid flow
B. Heat conduction
C. Radiation
D. Work done

Q72. In laminar flow, head loss is proportional to:

A. Velocity
B. Velocity²
C. Velocity³
D. √Velocity

Q73. The Prandtl number is:

A. ν / α
B. α / ν
C. μ / ρ
D. ρ / μ

Q74. An ideal gas undergoes an adiabatic process; the relation between pressure and volume is:

A. PV = constant
B. P V^γ = constant
C. P / V = constant
D. P + V = constant

Q75. In a venturimeter, flow rate is measured using:

A. Pressure difference
B. Velocity difference
C. Height difference
D. None of the above

Section D – Strength of Materials & Engineering Mechanics (Q76–100)

Q76. Stress is defined as:

A. Force × Area
B. Force / Area
C. Area / Force
D. Work / Volume

Q77. Strain is defined as:

A. Stress × Young’s modulus
B. Change in length / Original length
C. Force / Area
D. Work done / Volume

Q78. Factor of Safety (FOS) =

A. Ultimate load / Working load
B. Working load / Ultimate load
C. Yield load × Working load
D. None of the above

Q79. A simply supported beam with uniform load:

A. Maximum shear at mid-span
B. Maximum bending moment at supports
C. Maximum bending moment at mid-span
D. None

Q80. Torsion in shafts depends on:

A. Length only
B. Material only
C. Torque, diameter, and material
D. Diameter only

Q81. Moment of inertia of rectangular section about centroidal axis:

A. bh³ / 12
B. b³h / 12
C. bh³ / 6
D. b³h / 6

Q82. A spring is subjected to load, the energy stored is:

A. 1/2 k x²
B. k x²
C. 2 k x²
D. k / x²

Q83. Poisson’s ratio is:

A. Lateral strain / Longitudinal strain
B. Longitudinal strain / Lateral strain
C. Stress / Strain
D. Strain / Stress

Q84. Shear stress in circular shaft =

A. Torque × radius / J
B. Torque × radius² / J
C. Torque / radius
D. Torque / J

Q85. The elastic limit of a material is:

A. Maximum stress it can withstand
B. Stress beyond which permanent deformation occurs
C. Yield point
D. Breaking stress

Q86. In a simply supported beam, shear force at supports is:

A. Zero
B. Maximum
C. Mid-value
D. None

Q87. The polar moment of inertia is used to calculate:

A. Bending stress
B. Torsional stress
C. Shear force
D. Axial stress

Q88. In a cantilever beam, the deflection at free end is proportional to:

A. Load × length³ / (EI)
B. Load × length / (EI)
C. Load × length² / (EI)
D. Load × length⁴ / (EI)

Q89. Work done by a force =

A. Force × Time
B. Force × Distance in direction of force
C. Force / Distance
D. Force × Velocity

Q90. Unit of stress in SI system:

A. Pascal (Pa)
B. Newton (N)
C. Joule (J)
D. N·m

Q91. Centroid of a uniform rectangular section is located:

A. At the corner
B. At the geometric center
C. At midpoint of one side
D. Depends on orientation

Q92. The slope of stress-strain curve in elastic region gives:

A. Young’s modulus
B. Poisson’s ratio
C. Shear modulus
D. Bulk modulus

Q93. In rolling, deformation occurs mainly due to:

A. Shearing
B. Compression
C. Torsion
D. Bending

Q94. The load at which a column fails by buckling depends on:

A. Material only
B. Slenderness ratio and material
C. Length only
D. Cross-sectional area only

Q95. The SI unit of torque:

A. N·m
B. Nm²
C. N/m²
D. Pa

Q96. The property of a material to resist sudden impact is called:

A. Hardness
B. Toughness
C. Strength
D. Ductility

Q97. In a pulley system, mechanical advantage =

A. Load / Effort
B. Effort / Load
C. Load × Effort
D. Load – Effort

Q98. The area under stress-strain curve gives:

A. Work done per unit volume
B. Energy per unit volume
C. Both A and B
D. None

Q99. The maximum shear stress theory is used for:

A. Ductile materials
B. Brittle materials
C. All materials
D. None

Q100. A mechanical system consists of 2 shafts and 3 pulleys. Which is used to transmit power efficiently over distance?

A. Belt drive
B. Chain drive
C. Gear drive
D. All of the above

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Q.No	Answer	Q.No	Answer	Q.No	Answer	Q.No	Answer
1	A	26	D	51	B	76	B
2	B	27	D	52	B	77	B
3	B	28	B	53	A	78	A
4	A	29	B	54	A	79	C
5	A	30	B	55	B	80	C
6	C	31	B	56	A	81	A
7	C	32	A	57	B	82	A
8	A	33	B	58	B	83	A
9	A	34	A	59	B	84	A
10	B	35	B	60	B	85	B
11	C	36	A	61	B	86	B
12	B	37	B	62	B	87	B
13	B	38	C	63	A	88	A
14	B	39	D	64	C	89	B
15	A	40	D	65	A	90	A
16	B	41	A	66	A	91	B
17	C	42	D	67	D	92	A
18	D	43	B	68	B	93	B
19	B	44	D	69	A	94	B
20	C	45	B	70	A	95	A
21	A	46	C	71	B	96	B
22	B	47	B	72	B	97	A
23	B	48	D	73	A	98	C
24	B	49	B	74	B	99	A
25	A	50	D	75	B	100	A

Disclaimer

This mock test is created for educational and practice purposes only. All questions are original and designed to simulate the BARC ST Mechanical Trade exam. This website is not affiliated with or endorsed by BARC.