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RRB JE CBT 2 Mechanical Engineering Practice Paper 01 (Exam Pattern, Solved Set)

RRB JE (Junior Engineer) • 2026 • 150 Questions • Free practice with solutions

Subjects included:General Awareness (15)General Science (25)Computer Knowledge (10)Mechanical Engineering (SSC JE) (100)
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Showing 150 Questions with Step-by-Step Solutions
Q1General Awareness
Medium
The Indian Railways Institute of Civil Engineering (IRICEN) is located in:
A. Pune
B. Nashik
C. Jamalpur
D. Vadodara
View answer and explanation
Correct Option: A
IRIEEN is in Nashik and IRIMEE in Jamalpur.
Q2General Awareness
Medium
The Indian Railways Institute of Mechanical and Electrical Engineering (IRIMEE) is located in:
A. Pune
B. Jamalpur
C. Secunderabad
D. Lucknow
View answer and explanation
Correct Option: B
Jamalpur is in Bihar.
Q3General Awareness
Medium
The Indian Railways Institute of Electrical Engineering (IRIEEN) is located in:
A. Jamalpur
B. Pune
C. Nashik
D. Kolkata
View answer and explanation
Correct Option: C
It trains electrical engineering officers.
Q4General Awareness
Medium
The Indian Railways Institute of Signal Engineering and Telecommunications (IRISET) is located in:
A. Pune
B. Lucknow
C. Nashik
D. Secunderabad
View answer and explanation
Correct Option: D
It trains signal and telecom staff.
Q5General Awareness
Medium
South India's first railway line, opened in 1856, ran from Royapuram (Madras) to:
A. Wallajah Road (Arcot)
B. Bengaluru
C. Tiruchirappalli
D. Pondicherry
View answer and explanation
Correct Option: A
It opened on 1 July 1856.
Q6General Awareness
Easy
The track width of Indian broad gauge is:
A. 1,435 mm
B. 1,676 mm
C. 1,000 mm
D. 762 mm
View answer and explanation
Correct Option: B
1,435 mm is standard gauge, used on metro lines.
Q7General Awareness
Easy
The track width of metre gauge is:
A. 762 mm
B. 1,676 mm
C. 1,000 mm
D. 610 mm
View answer and explanation
Correct Option: C
Most metre-gauge lines have been converted to broad gauge.
Q8General Awareness
Medium
Indian Railways electrifies its main lines at:
A. 11 kV AC, 60 Hz
B. 1,500 V DC
C. 750 V DC
D. 25 kV AC, 50 Hz
View answer and explanation
Correct Option: D
Single-phase 25 kV AC overhead traction.
Q9General Awareness
Medium
The headquarters of Konkan Railway Corporation is at:
A. CBD Belapur, Navi Mumbai
B. Goa
C. Mangaluru
D. Ratnagiri
View answer and explanation
Correct Option: A
The line runs from Roha to Thokur.
Q10General Awareness
Easy
The first line of the Delhi Metro opened in:
A. 1998
B. 2002
C. 2005
D. 2010
View answer and explanation
Correct Option: B
Shahdara to Tis Hazari, December 2002.
Q11General Awareness
Easy
The Bureau of Indian Standards (BIS) has its headquarters in:
A. Kolkata
B. Mumbai
C. New Delhi
D. Bengaluru
View answer and explanation
Correct Option: C
BIS sets Indian Standards (IS codes).
Q12General Awareness
Easy
ISO 9001 is a standard for:
A. Occupational safety
B. Environmental management
C. Information security
D. Quality management systems
View answer and explanation
Correct Option: D
ISO 14001 is for environmental management.
Q13General Awareness
Easy
The National Highways Authority of India works under the:
A. Ministry of Road Transport and Highways
B. Ministry of Railways
C. Ministry of Home Affairs
D. NITI Aayog
View answer and explanation
Correct Option: A
It develops and maintains national highways.
Q14General Awareness
Easy
The Smart Cities Mission was launched in:
A. 2012
B. 2015
C. 2018
D. 2020
View answer and explanation
Correct Option: B
On 25 June 2015.
Q15General Awareness
Medium
The AMRUT scheme mainly deals with urban:
A. Airports
B. Metro rail
C. Water supply and sewerage
D. Housing loans
View answer and explanation
Correct Option: C
Atal Mission for Rejuvenation and Urban Transformation.
Q16General Science
Medium
The dimensional formula of force is:
A. [M L⁻¹ T⁻²]
B. [M L² T⁻²]
C. [M L T⁻¹]
D. [M L T⁻²]
View answer and explanation
Correct Option: D
Force = mass x acceleration.
Q17General Science
Easy
The CGS unit of work is the:
A. Erg
B. Joule
C. Dyne
D. Watt
View answer and explanation
Correct Option: A
1 joule = 10^7 erg.
Q18General Science
Easy
One newton is equal to:
A. 10³ dyne
B. 10⁵ dyne
C. 10⁷ dyne
D. 10² dyne
View answer and explanation
Correct Option: B
1 N = 1 kg m/s^2 = 1,000 g x 100 cm/s^2.
Q19General Science
Easy
The SI unit of Young's modulus is the:
A. Joule
B. Newton
C. Pascal (N/m²)
D. Metre
View answer and explanation
Correct Option: C
It is stress divided by strain, and strain has no unit.
Q20General Science
Easy
Stress is defined as:
A. Work per unit volume
B. Change in length per unit length
C. Force times area
D. Force per unit area
View answer and explanation
Correct Option: D
Strain is the change in length per unit length.
Q21General Science
Medium
Hooke's law holds only within the:
A. Elastic limit
B. Breaking point
C. Yield point and beyond
D. Plastic range
View answer and explanation
Correct Option: A
Within it, stress is proportional to strain.
Q22General Science
Medium
The specific heat capacity of water is about:
A. 418.6 J/(kg K)
B. 4,186 J/(kg K)
C. 41.86 J/(kg K)
D. 4.186 J/(kg K)
View answer and explanation
Correct Option: B
About 4.2 kJ per kg per kelvin.
Q23General Science
Easy
The SI unit of surface tension is:
A. N m
B. N/m²
C. N/m
D. J/s
View answer and explanation
Correct Option: C
Force per unit length.
Q24General Science
Medium
The SI unit of dynamic viscosity is:
A. J/kg
B. N/m
C. m²/s
D. Pa s
View answer and explanation
Correct Option: D
Kinematic viscosity is measured in m^2/s.
Q25General Science
Medium
Bernoulli's principle is based on the conservation of:
A. Energy
B. Mass
C. Momentum
D. Charge
View answer and explanation
Correct Option: A
Pressure, kinetic and potential energy per unit volume stay constant along a streamline.
Q26General Science
Medium
Which of these does NOT obey Ohm's law?
A. A copper wire
B. A semiconductor diode
C. A nichrome wire at constant temperature
D. A carbon resistor
View answer and explanation
Correct Option: B
Its current-voltage graph is not a straight line.
Q27General Science
Easy
The resistance of a metallic conductor:
A. Does not depend on temperature
B. Decreases with temperature
C. Increases with temperature
D. Becomes zero at room temperature
View answer and explanation
Correct Option: C
Metals have a positive temperature coefficient.
Q28General Science
Medium
The electric field inside a charged hollow conductor is:
A. Infinite
B. Maximum
C. Equal to that at the surface
D. Zero
View answer and explanation
Correct Option: D
Charge resides on the outer surface.
Q29General Science
Easy
The SI unit of capacitance is the:
A. Farad
B. Henry
C. Ohm
D. Tesla
View answer and explanation
Correct Option: A
1 farad = 1 coulomb per volt.
Q30General Science
Medium
Lenz's law is a consequence of the conservation of:
A. Charge
B. Energy
C. Momentum
D. Mass
View answer and explanation
Correct Option: B
The induced current opposes the change that produces it.
Q31Computer Knowledge
Easy
CPU stands for:
A. Central Processing Unit
B. Central Program Unit
C. Computer Processing Unit
D. Control Processing Utility
View answer and explanation
Correct Option: A
It carries out instructions.
Q32Computer Knowledge
Easy
Which memory loses its contents when power is switched off?
A. ROM
B. RAM
C. Hard disk
D. Pen drive
View answer and explanation
Correct Option: B
RAM is volatile.
Q33Computer Knowledge
Easy
ROM is:
A. An input device
B. Volatile memory
C. Non-volatile, read-only memory
D. A type of printer
View answer and explanation
Correct Option: C
It stores firmware such as the BIOS.
Q34Computer Knowledge
Easy
1 kilobyte (KB) is equal to:
A. 100 bytes
B. 1,000 bits
C. 1,024 bits
D. 1,024 bytes
View answer and explanation
Correct Option: D
2^10 bytes.
Q35Computer Knowledge
Easy
1 byte is equal to:
A. 8 bits
B. 4 bits
C. 16 bits
D. 10 bits
View answer and explanation
Correct Option: A
A bit is a single 0 or 1.
Q36Computer Knowledge
Easy
The binary form of decimal 10 is:
A. 1001
B. 1010
C. 1100
D. 0110
View answer and explanation
Correct Option: B
8 + 2 = 10.
Q37Computer Knowledge
Easy
The decimal value of binary 1101 is:
A. 14
B. 11
C. 13
D. 12
View answer and explanation
Correct Option: C
8 + 4 + 0 + 1 = 13.
Q38Computer Knowledge
Easy
Which of these is an input device?
A. Speaker
B. Monitor
C. Printer
D. Keyboard
View answer and explanation
Correct Option: D
The others are output devices.
Q39Computer Knowledge
Easy
Which of these is an output device?
A. Printer
B. Mouse
C. Scanner
D. Keyboard
View answer and explanation
Correct Option: A
It gives information out of the computer.
Q40Computer Knowledge
Easy
Which of these is an operating system?
A. MS Word
B. Linux
C. Google Chrome
D. Oracle Database
View answer and explanation
Correct Option: B
Windows, Linux and macOS are operating systems.
Q41General Science
Easy
Global warming is mainly caused by:
A. Nitrogen in the air
B. Oxygen in the air
C. Greenhouse gases such as carbon dioxide
D. Ozone in the stratosphere
View answer and explanation
Correct Option: C
They trap heat radiated by the Earth.
Q42General Science
Medium
The Kyoto Protocol deals with:
A. Wetland conservation
B. Protecting the ozone layer
C. Trade in endangered species
D. Reducing greenhouse gas emissions
View answer and explanation
Correct Option: D
Adopted in 1997.
Q43General Science
Medium
The Montreal Protocol deals with:
A. Ozone-depleting substances
B. Greenhouse gases
C. Plastic waste
D. Biodiversity
View answer and explanation
Correct Option: A
It phased out CFCs.
Q44General Science
Medium
The Paris Agreement aims to limit global warming to:
A. Exactly 4 °C
B. Well below 2 °C above pre-industrial levels
C. 0 °C
D. 5 °C by 2100
View answer and explanation
Correct Option: B
With efforts to limit it to 1.5 °C.
Q45General Science
Medium
BOD (Biochemical Oxygen Demand) of water indicates the amount of:
A. Heavy metals
B. Dissolved salts
C. Organic pollution that microbes break down
D. Radioactivity
View answer and explanation
Correct Option: C
It is the oxygen used by microbes to decompose organic matter.
Q46General Science
Easy
A high BOD value means the water is:
A. Colder
B. Cleaner
C. Softer
D. More polluted
View answer and explanation
Correct Option: D
More organic matter is present.
Q47General Science
Easy
PM2.5 refers to particulate matter with a diameter of:
A. 2.5 micrometres or less
B. 2.5 millimetres or less
C. 25 micrometres or more
D. 2.5 centimetres
View answer and explanation
Correct Option: A
These fine particles go deep into the lungs.
Q48General Science
Easy
Noise is measured in:
A. Hertz
B. Decibels
C. Lux
D. Pascals
View answer and explanation
Correct Option: B
A logarithmic scale.
Q49General Science
Medium
The CPCB daytime ambient noise limit for residential areas is:
A. 65 dB(A)
B. 75 dB(A)
C. 55 dB(A)
D. 45 dB(A)
View answer and explanation
Correct Option: C
The night-time limit is 45 dB(A).
Q50General Science
Medium
Which device removes fine particles from chimney gases using an electric charge?
A. Cyclone fan
B. Scrubber only
C. Catalytic converter
D. Electrostatic precipitator
View answer and explanation
Correct Option: D
Charged particles stick to collecting plates.
Q51Mechanical Engineering (SSC JE)
Easy
The zeroth law of thermodynamics is the basis for the measurement of
A. pressure
B. work
C. entropy
D. temperature
View answer and explanation
Correct Option: D
If two bodies are each in thermal equilibrium with a third, they are in equilibrium with each other. This makes a thermometer meaningful.
Q52Mechanical Engineering (SSC JE)
Easy
A Carnot engine works between reservoirs at 800 K and 300 K. Its efficiency is
A. 60 percent
B. 72.5 percent
C. 37.5 percent
D. 62.5 percent
View answer and explanation
Correct Option: D
η = 1 − T2/T1 = 1 − 300/800 = 0.625.
Q53Mechanical Engineering (SSC JE)
Easy
The value of the universal gas constant is
A. 83.14 kJ/kmol·K
B. 0.287 kJ/kmol·K
C. 8.314 kJ/kmol·K
D. 1.4 kJ/kmol·K
View answer and explanation
Correct Option: C
R̄ = 8.314 kJ/kmol·K. The gas constant of air, 0.287 kJ/kg·K, is R̄ divided by the molar mass 28.97.
Q54Mechanical Engineering (SSC JE)
Easy
For a closed system undergoing a complete cycle, the net heat transfer is equal to
A. the change in internal energy
B. the change in enthalpy
C. zero
D. the net work done
View answer and explanation
Correct Option: D
Over a cycle ΔU = 0, so by the first law ∮δQ = ∮δW.
Q55Mechanical Engineering (SSC JE)
Easy
The ratio of specific heats γ for air at ordinary temperatures is about
A. 1.33
B. 1.67
C. 1.0
D. 1.4
View answer and explanation
Correct Option: D
Air is mostly diatomic, with γ = Cp/Cv ≈ 1.4. Monatomic gases give 1.67.
Q56Mechanical Engineering (SSC JE)
Easy
In a reversible adiabatic process, the entropy of the system
A. decreases
B. increases
C. remains constant
D. becomes zero
View answer and explanation
Correct Option: C
With δQ = 0 and no irreversibility, dS = δQrev/T = 0. Such a process is called isentropic.
Q57Mechanical Engineering (SSC JE)
Easy
For an ideal gas, Cp − Cv is equal to
A. the characteristic gas constant R
B. γ
C. zero
D. the universal gas constant for every gas
View answer and explanation
Correct Option: A
This is Mayer’s relation, Cp − Cv = R, where R is the specific gas constant of that gas.
Q58Mechanical Engineering (SSC JE)
Easy
A throttling process is
A. isothermal for every fluid
B. isenthalpic
C. isochoric
D. isentropic
View answer and explanation
Correct Option: B
In throttling through a valve or porous plug, h1 = h2 (adiabatic, no work, negligible change in kinetic energy), but entropy increases.
Q59Mechanical Engineering (SSC JE)
Hard
The air standard efficiency of an Otto cycle with compression ratio 8 and γ = 1.4 is about
A. 43.5 percent
B. 56.5 percent
C. 75 percent
D. 63.5 percent
View answer and explanation
Correct Option: B
η = 1 − 1/r^(γ−1) = 1 − 1/8^0.4 = 1 − 1/2.297 = 0.565.
Q60Mechanical Engineering (SSC JE)
Medium
The critical temperature of water is about
A. 374 °C
B. 273 °C
C. 100 °C
D. 547 °C
View answer and explanation
Correct Option: A
At 374 °C and 221 bar the liquid and vapour phases become indistinguishable.
Q61Mechanical Engineering (SSC JE)
Easy
The Kelvin-Planck statement of the second law deals with
A. a heat engine
B. a heat pump
C. an adiabatic compressor
D. a refrigerator
View answer and explanation
Correct Option: A
No cyclic heat engine can convert all the heat from a single reservoir into work. The Clausius statement deals with refrigerators.
Q62Mechanical Engineering (SSC JE)
Medium
Reheating the steam in a Rankine cycle mainly
A. improves the dryness of the steam at the turbine exhaust
B. lowers the boiler pressure
C. reduces the work output of the turbine
D. increases the condenser pressure
View answer and explanation
Correct Option: A
Passing the partly expanded steam through the boiler again reduces moisture in the last stages, which protects the blades.
Q63Mechanical Engineering (SSC JE)
Easy
The SI unit of kinematic viscosity is
A. N/m²
B. kg/m·s
C. N·s/m²
D. m²/s
View answer and explanation
Correct Option: D
ν = μ/ρ, so its unit is m²/s. N·s/m² is the unit of dynamic viscosity.
Q64Mechanical Engineering (SSC JE)
Hard
A difference of 100 mm of mercury (density 13 600 kg/m³) corresponds to a pressure difference of about
A. 13.3 kPa
B. 133 kPa
C. 0.98 kPa
D. 9.81 kPa
View answer and explanation
Correct Option: A
Δp = ρgh = 13 600 × 9.81 × 0.1 = 13 342 Pa ≈ 13.3 kPa.
Q65Mechanical Engineering (SSC JE)
Easy
A Pitot tube is used to measure
A. the density of a fluid
B. the viscosity of a fluid
C. the surface tension
D. the local velocity of flow
View answer and explanation
Correct Option: D
It senses the stagnation pressure, and with the static pressure gives the velocity head.
Q66Mechanical Engineering (SSC JE)
Easy
The Reynolds number is the ratio of
A. viscous forces to inertial forces
B. inertial forces to viscous forces
C. pressure forces to surface tension forces
D. gravity forces to inertial forces
View answer and explanation
Correct Option: B
Re = ρVD/μ. It decides whether flow is laminar or turbulent.
Q67Mechanical Engineering (SSC JE)
Easy
Cavitation in a pump occurs when the pressure at some point in the liquid falls below
A. the atmospheric pressure
B. the delivery pressure
C. the vapour pressure of the liquid at that temperature
D. the critical pressure
View answer and explanation
Correct Option: C
Vapour bubbles form and later collapse violently on reaching higher pressure, causing noise, vibration and pitting.
Q68Mechanical Engineering (SSC JE)
Medium
A Kaplan turbine is
A. an impulse turbine for high heads
B. a radial flow turbine for very high heads
C. a tangential flow turbine
D. an axial flow reaction turbine for low heads
View answer and explanation
Correct Option: D
The Kaplan runner has adjustable blades and suits large discharges at low heads.
Q69Mechanical Engineering (SSC JE)
Medium
The overall efficiency of a centrifugal pump is the product of
A. mechanical and thermal efficiencies
B. volumetric and thermal efficiencies
C. hydraulic and thermal efficiencies
D. hydraulic, mechanical and volumetric efficiencies
View answer and explanation
Correct Option: D
η = ηh × ηm × ηv, covering the losses in the flow passages, the bearings and the leakage.
Q70Mechanical Engineering (SSC JE)
Easy
An air vessel is fitted to a reciprocating pump to
A. cool the cylinder
B. prime the pump
C. obtain a uniform discharge and reduce friction and acceleration head
D. increase the suction lift
View answer and explanation
Correct Option: C
The vessel absorbs surges of flow, so a steadier stream flows in the pipe and the pump can run at higher speed.
Q71Mechanical Engineering (SSC JE)
Easy
In a hydraulic press, the small piston has an area of 10 cm² and the large piston 500 cm². A force of 200 N on the small piston produces a force on the large piston of
A. 100 kN
B. 10 kN
C. 1 kN
D. 4 kN
View answer and explanation
Correct Option: B
Pressure is the same on both pistons: F2 = F1 × (A2/A1) = 200 × 50 = 10 000 N.
Q72Mechanical Engineering (SSC JE)
Easy
In the Buckingham π theorem, if there are n variables and m fundamental dimensions, the number of dimensionless groups is
A. n + m
B. n − m
C. n × m
D. m − n
View answer and explanation
Correct Option: B
The variables are reduced to (n − m) independent dimensionless π terms.
Q73Mechanical Engineering (SSC JE)
Medium
Separation of the boundary layer from a surface takes place because of
A. a high free stream velocity only
B. zero velocity at the free stream
C. a favourable pressure gradient
D. an adverse pressure gradient
View answer and explanation
Correct Option: D
When the pressure rises in the flow direction, the fluid near the wall loses momentum and the flow reverses.
Q74Mechanical Engineering (SSC JE)
Medium
The draft tube of a reaction turbine
A. converts kinetic energy of the exit water into pressure and lets the runner be set above the tail water
B. works as a governor
C. increases the speed of the runner
D. reduces the discharge
View answer and explanation
Correct Option: A
A gradually widening tube recovers energy and keeps the runner exit pressure below atmospheric, adding to the effective head.
Q75Mechanical Engineering (SSC JE)
Easy
Air of density 1.2 kg/m³ flows at 10 m/s through a duct of area 0.01 m². The mass flow rate is
A. 0.12 kg/s
B. 0.012 kg/s
C. 12 kg/s
D. 1.2 kg/s
View answer and explanation
Correct Option: A
ṁ = ρAV = 1.2 × 0.01 × 10 = 0.12 kg/s.
Q76Mechanical Engineering (SSC JE)
Easy
The flow of a gas is supersonic when the Mach number is
A. less than 1
B. greater than 1
C. equal to 0
D. equal to 0.5
View answer and explanation
Correct Option: B
Mach number M = V/c, where c is the speed of sound. M = 1 is sonic flow.
Q77Mechanical Engineering (SSC JE)
Easy
Fourier’s law of heat conduction states that the heat flux is proportional to
A. the square of the temperature
B. the temperature gradient
C. the surface area only
D. the fourth power of temperature
View answer and explanation
Correct Option: B
q = −k dT/dx, with the negative sign showing that heat flows from hot to cold.
Q78Mechanical Engineering (SSC JE)
Easy
A plane wall has a thermal conductivity of 0.5 W/m·K and a thickness of 0.2 m. The temperature difference across it is 40 °C. The heat flux is
A. 4 W/m²
B. 100 W/m²
C. 10 W/m²
D. 1000 W/m²
View answer and explanation
Correct Option: B
q = k ΔT / L = 0.5 × 40 / 0.2 = 100 W/m².
Q79Mechanical Engineering (SSC JE)
Easy
According to the Stefan-Boltzmann law, if the absolute temperature of a black body is doubled, the emissive power increases by a factor of
A. 8
B. 4
C. 2
D. 16
View answer and explanation
Correct Option: D
E = σT⁴, so doubling T gives 2⁴ = 16 times the emissive power.
Q80Mechanical Engineering (SSC JE)
Medium
The Nusselt number is defined as
A. hL / k
B. ρVL / μ
C. V / c
D. μ cp / k
View answer and explanation
Correct Option: A
It is the ratio of convective to conductive heat transfer across a boundary.
Q81Mechanical Engineering (SSC JE)
Easy
Fins are provided on a surface to
A. lower the thermal conductivity
B. increase the weight
C. increase the surface area for heat transfer
D. reduce the heat transfer
View answer and explanation
Correct Option: C
More surface area to the fluid helps when the heat transfer coefficient is low, as with air.
Q82Mechanical Engineering (SSC JE)
Medium
The critical radius of insulation for a cylinder is given by
A. kh
B. h / k
C. 2k / h
D. k / h
View answer and explanation
Correct Option: D
Insulation below this radius increases the heat loss, because the outer area grows faster than the resistance of the insulation.
Q83Mechanical Engineering (SSC JE)
Easy
Hooke’s law is valid up to the
A. ultimate stress
B. yield point of every material
C. proportional limit
D. breaking point
View answer and explanation
Correct Option: C
Stress is proportional to strain only up to the proportional limit.
Q84Mechanical Engineering (SSC JE)
Easy
The modulus of elasticity of mild steel is about
A. 100 GPa
B. 200 GPa
C. 70 GPa
D. 400 GPa
View answer and explanation
Correct Option: B
Steel is about 200 GPa, aluminium about 70 GPa and cast iron around 100 GPa.
Q85Mechanical Engineering (SSC JE)
Hard
A 20 mm diameter rod carries an axial pull of 100 kN. The stress developed is about
A. 159 MPa
B. 637 MPa
C. 31.8 MPa
D. 318 MPa
View answer and explanation
Correct Option: D
A = π × 20²/4 = 314.2 mm². σ = 100 000 / 314.2 = 318.3 MPa.
Q86Mechanical Engineering (SSC JE)
Medium
For brittle materials, the most suitable theory of failure is
A. the maximum shear strain energy theory
B. the distortion energy theory (von Mises)
C. the maximum shear stress theory (Tresca)
D. the maximum principal stress theory (Rankine)
View answer and explanation
Correct Option: D
Brittle materials fail by fracture when the largest principal stress reaches the ultimate strength, as the Rankine theory assumes.
Q87Mechanical Engineering (SSC JE)
Easy
In the Brinell hardness test, the indenter is
A. a diamond pyramid
B. a hardened steel (or tungsten carbide) ball
C. a steel cone
D. a diamond cone
View answer and explanation
Correct Option: B
Brinell uses a ball. Vickers uses a diamond pyramid and Rockwell C uses a diamond cone.
Q88Mechanical Engineering (SSC JE)
Easy
A simply supported beam of span 4 m carries a central point load of 10 kN. The maximum bending moment is
A. 40 kN·m
B. 10 kN·m
C. 20 kN·m
D. 5 kN·m
View answer and explanation
Correct Option: B
M = WL/4 = 10 × 4 / 4 = 10 kN·m.
Q89Mechanical Engineering (SSC JE)
Easy
A point of contraflexure on a beam is a point where
A. the deflection is maximum
B. the slope is zero
C. the shear force is maximum
D. the bending moment changes sign
View answer and explanation
Correct Option: D
At such a point the beam changes from sagging to hogging, and the moment is usually zero.
Q90Mechanical Engineering (SSC JE)
Easy
In a thin cylindrical shell under internal pressure, the ratio of hoop stress to longitudinal stress is
A. 4
B. 0.5
C. 2
D. 1
View answer and explanation
Correct Option: C
σh = pd/2t and σl = pd/4t, so the ratio is 2.
Q91Mechanical Engineering (SSC JE)
Easy
Charpy and Izod impact tests measure
A. the toughness of a material
B. the fatigue limit of a material
C. the creep strength of a material
D. the hardness of a material
View answer and explanation
Correct Option: A
The energy absorbed by a notched specimen when it breaks is a measure of toughness.
Q92Mechanical Engineering (SSC JE)
Easy
The factor of safety based on the ultimate strength is the ratio of
A. working stress to ultimate stress
B. ultimate stress to working (allowable) stress
C. ultimate load to yield load
D. yield stress to ultimate stress
View answer and explanation
Correct Option: B
FOS = σu/σw. Ductile materials are often based on yield stress instead.
Q93Mechanical Engineering (SSC JE)
Easy
The number of degrees of freedom of a planar four-bar mechanism is
A. 3
B. 1
C. 2
D. 0
View answer and explanation
Correct Option: B
Using Gruebler’s equation F = 3(n − 1) − 2j − h = 3 × 3 − 2 × 4 − 0 = 1.
Q94Mechanical Engineering (SSC JE)
Easy
A flywheel is used to
A. balance the reciprocating masses
B. reduce the fluctuation of speed during a cycle by storing energy
C. transmit power between shafts
D. control the mean speed against changes in load
View answer and explanation
Correct Option: B
It absorbs energy when the speed rises and gives it back when the speed falls. A governor controls the mean speed.
Q95Mechanical Engineering (SSC JE)
Easy
A governor in an engine is used to
A. increase the torque
B. reduce vibrations
C. maintain the mean speed when the load varies
D. reduce the fluctuations in speed within a cycle
View answer and explanation
Correct Option: C
It adjusts the fuel supply to the engine in response to load changes.
Q96Mechanical Engineering (SSC JE)
Easy
A gear has a pitch circle diameter of 120 mm and 40 teeth. Its module is
A. 30 mm
B. 4.8 mm
C. 3 mm
D. 0.33 mm
View answer and explanation
Correct Option: C
m = d/z = 120/40 = 3 mm.
Q97Mechanical Engineering (SSC JE)
Easy
The pressure angle commonly used for standard involute gear teeth is
A. 45°
B. 60°
C. 5°
D. 20°
View answer and explanation
Correct Option: D
14.5° was used earlier but 20° full-depth teeth are now standard because they are stronger and avoid interference with fewer teeth.
Q98Mechanical Engineering (SSC JE)
Easy
For a flat belt drive, the ratio of tight side to slack side tension is
A. e^(−μθ)
B. μθ
C. e^(μθ)
D. θ/μ
View answer and explanation
Correct Option: C
T1/T2 = e^(μθ), where θ is the angle of contact in radians.
Q99Mechanical Engineering (SSC JE)
Medium
For a rotating system to be in static balance, it is necessary that
A. the resultant couple is zero only
B. the speed is zero
C. the resultant centrifugal force is zero
D. the shaft is rigid
View answer and explanation
Correct Option: C
Static balance needs ΣF = 0. Dynamic balance also needs the resultant couple to be zero.
Q100Mechanical Engineering (SSC JE)
Hard
A spring-mass system has a stiffness of 3600 N/m and a mass of 4 kg. Its natural frequency is
A. 60 rad/s
B. 30 rad/s
C. 900 rad/s
D. 15 rad/s
View answer and explanation
Correct Option: B
ωn = √(k/m) = √(3600/4) = √900 = 30 rad/s.
Q101Mechanical Engineering (SSC JE)
Medium
The base circle of a cam is
A. the smallest circle drawn from the cam centre tangent to the cam profile
B. the circle that passes through the pitch point
C. the circle through the follower tip
D. the largest circle that can be drawn on the cam
View answer and explanation
Correct Option: A
The follower is at its lowest position when it touches the base circle.
Q102Mechanical Engineering (SSC JE)
Easy
A Hooke’s joint is used to connect two shafts which
A. are collinear
B. are parallel
C. are perpendicular and do not intersect
D. intersect at an angle
View answer and explanation
Correct Option: D
A universal joint transmits motion between intersecting shafts, though the speed of the driven shaft fluctuates.
Q103Mechanical Engineering (SSC JE)
Easy
The Goodman diagram is used in the design of machine members subjected to
A. fatigue (fluctuating loads)
B. impact loads only
C. static loads only
D. thermal loads only
View answer and explanation
Correct Option: A
It relates the mean stress and the alternating stress for a given factor of safety against fatigue failure.
Q104Mechanical Engineering (SSC JE)
Medium
For most steels, the endurance limit is roughly
A. 0.2 times the ultimate tensile strength
B. 1.2 times the ultimate tensile strength
C. 0.9 times the ultimate tensile strength
D. half of the ultimate tensile strength
View answer and explanation
Correct Option: D
For steels with Sut below about 1400 MPa, Se′ ≈ 0.5 Sut for a polished specimen.
Q105Mechanical Engineering (SSC JE)
Medium
The taper on a standard sunk key is generally
A. zero
B. 1 in 100
C. 1 in 20
D. 1 in 10
View answer and explanation
Correct Option: B
Taper keys are tapered on the top at 1 in 100 so that driving them in makes a tight fit.
Q106Mechanical Engineering (SSC JE)
Hard
A deep groove ball bearing has a dynamic load rating C of 20 kN and carries an equivalent load of 10 kN. Its rated life L10 is
A. 2 million revolutions
B. 8 million revolutions
C. 4 million revolutions
D. 16 million revolutions
View answer and explanation
Correct Option: B
For ball bearings L10 = (C/P)³ = 2³ = 8 million revolutions.
Q107Mechanical Engineering (SSC JE)
Medium
The Wahl factor in a helical spring accounts for
A. the effect of direct shear and the curvature of the coil
B. the length of the spring
C. the surface finish
D. the number of active coils
View answer and explanation
Correct Option: A
The factor K = (4C − 1)/(4C − 4) + 0.615/C corrects the simple torsion formula for these effects.
Q108Mechanical Engineering (SSC JE)
Easy
Stress concentration at a change of section can be reduced by
A. increasing the surface roughness
B. providing a generous fillet radius
C. making the corner sharp
D. adding a small hole near the corner
View answer and explanation
Correct Option: B
A smooth transition lets the force flow lines change direction gradually.
Q109Mechanical Engineering (SSC JE)
Medium
A hollow shaft compared with a solid shaft of the same weight and material is
A. equal in strength
B. weaker in torsion
C. cheaper to make
D. stronger and stiffer in torsion
View answer and explanation
Correct Option: D
Material removed from the centre carries little stress. Placing it farther out raises the polar moment of inertia.
Q110Mechanical Engineering (SSC JE)
Easy
A key may fail by
A. corrosion only
B. shearing and crushing
C. buckling only
D. creep only
View answer and explanation
Correct Option: B
The torque is transmitted by shear across the key and by bearing (crushing) on its sides.
Q111Mechanical Engineering (SSC JE)
Easy
In a four-stroke engine, one power stroke occurs in every
A. four revolutions of the crankshaft
B. two revolutions of the crankshaft
C. half a revolution of the crankshaft
D. one revolution of the crankshaft
View answer and explanation
Correct Option: B
Four strokes take 720° of crank rotation, giving one power stroke every two revolutions.
Q112Mechanical Engineering (SSC JE)
Easy
The cetane number is a measure of
A. the calorific value of petrol
B. the viscosity of lubricating oil
C. the knock resistance of petrol
D. the ignition quality of diesel fuel
View answer and explanation
Correct Option: D
A higher cetane number means a shorter ignition delay. The octane number rates petrol against knock.
Q113Mechanical Engineering (SSC JE)
Easy
The approximate stoichiometric air-fuel ratio for petrol is
A. 40 : 1
B. 25 : 1
C. 5 : 1
D. 14.7 : 1
View answer and explanation
Correct Option: D
About 14.7 kg of air is needed to burn 1 kg of petrol completely.
Q114Mechanical Engineering (SSC JE)
Hard
An engine develops 30 kW brake power while consuming fuel at 0.002 kg/s of calorific value 42 000 kJ/kg. The brake thermal efficiency is about
A. 50 percent
B. 28 percent
C. 35.7 percent
D. 42 percent
View answer and explanation
Correct Option: C
Heat supplied = 0.002 × 42 000 = 84 kW. η = 30/84 = 0.357.
Q115Mechanical Engineering (SSC JE)
Easy
In a diesel engine, the fuel is ignited by
A. a spark plug
B. the heat of compressed air
C. the exhaust gas
D. a glow plug in all conditions
View answer and explanation
Correct Option: B
Air is compressed to high temperature and the injected fuel self-ignites, which is why it is called a compression ignition engine.
Q116Mechanical Engineering (SSC JE)
Medium
The compression ratio of a typical compression ignition engine is in the range of
A. 4 to 6
B. 6 to 10
C. 30 to 40
D. 14 to 22
View answer and explanation
Correct Option: D
SI engines run at 6 to 10 to avoid knock, while CI engines need a much higher ratio to reach the self-ignition temperature.
Q117Mechanical Engineering (SSC JE)
Easy
A Carnot refrigerator works between 250 K and 300 K. Its COP is
A. 1.2
B. 5
C. 0.2
D. 6
View answer and explanation
Correct Option: B
COP = TL/(TH − TL) = 250/50 = 5.
Q118Mechanical Engineering (SSC JE)
Easy
One ton of refrigeration is equal to about
A. 7 kW
B. 0.35 kW
C. 3.5 kW
D. 1 kW
View answer and explanation
Correct Option: C
1 TR = 211 kJ/min = 3.517 kW, the rate of heat removal needed to freeze one tonne of water at 0 °C in 24 hours.
Q119Mechanical Engineering (SSC JE)
Easy
In a simple vapour compression refrigeration cycle, the refrigerant enters the compressor as
A. subcooled liquid
B. dry saturated or slightly superheated vapour
C. wet vapour with 50 percent dryness
D. saturated liquid
View answer and explanation
Correct Option: B
Liquid entering the compressor would damage the valves, so the vapour is kept dry.
Q120Mechanical Engineering (SSC JE)
Easy
The dew point temperature of air is the temperature at which
A. the dry bulb and wet bulb temperatures differ most
B. the humidity ratio is zero
C. water boils at atmospheric pressure
D. the air becomes saturated when cooled at constant pressure
View answer and explanation
Correct Option: D
On cooling below the dew point, vapour starts to condense.
Q121Mechanical Engineering (SSC JE)
Easy
The dry bulb and wet bulb temperatures of air are equal when the relative humidity is
A. 75 percent
B. 100 percent
C. 50 percent
D. 0 percent
View answer and explanation
Correct Option: B
In saturated air there is no evaporation from the wet bulb, so it reads the same as the dry bulb.
Q122Mechanical Engineering (SSC JE)
Medium
In a vapour absorption refrigeration system, the compressor of the vapour compression system is replaced by
A. a second condenser
B. an expansion valve
C. an absorber, a pump and a generator
D. a turbine
View answer and explanation
Correct Option: C
The refrigerant is absorbed in a solvent, pumped as a liquid and then driven off by heat in the generator, which uses much less work.
Q123Mechanical Engineering (SSC JE)
Easy
An economiser in a steam power plant is used to heat
A. the cooling water by the exhaust steam
B. the combustion air by the steam
C. the steam by the flue gases
D. the feed water by the flue gases
View answer and explanation
Correct Option: D
It recovers heat from the exit flue gases and raises boiler efficiency.
Q124Mechanical Engineering (SSC JE)
Easy
A Babcock and Wilcox boiler is a
A. fire tube boiler
B. water tube boiler
C. electric boiler
D. vertical fire tube boiler
View answer and explanation
Correct Option: B
Water flows in the tubes and the hot gases pass around them, which suits high pressures and large capacities.
Q125Mechanical Engineering (SSC JE)
Easy
The Parsons turbine is a
A. simple impulse turbine
B. reaction turbine
C. gas turbine
D. velocity compounded impulse turbine
View answer and explanation
Correct Option: B
The Parsons design has fixed and moving blades with a pressure drop in both. The De Laval turbine is an impulse turbine.
Q126Mechanical Engineering (SSC JE)
Easy
The main function of the condenser in a steam power plant is to
A. increase the boiler pressure
B. maintain a low back pressure so that more work is obtained from the turbine
C. dry the steam
D. supply hot water to the economiser
View answer and explanation
Correct Option: B
A low exhaust pressure gives a larger enthalpy drop in the turbine, and the condensate is reused as feed water.
Q127Mechanical Engineering (SSC JE)
Easy
In a nuclear reactor, the moderator is used to
A. slow down fast neutrons
B. absorb excess neutrons
C. remove heat from the core
D. shield against radiation
View answer and explanation
Correct Option: A
Slow (thermal) neutrons are far more likely to cause fission in U-235. Control rods absorb neutrons and the coolant removes heat.
Q128Mechanical Engineering (SSC JE)
Easy
A gas turbine plant works on the
A. Stirling cycle
B. Brayton cycle
C. Otto cycle
D. Rankine cycle
View answer and explanation
Correct Option: B
The Brayton cycle consists of isentropic compression, constant pressure heat addition, isentropic expansion and constant pressure heat rejection.
Q129Mechanical Engineering (SSC JE)
Hard
A hydroelectric plant has a flow of 10 m³/s under a head of 50 m with an overall efficiency of 90 percent. The power output is about
A. 4.41 MW
B. 4.9 MW
C. 0.49 MW
D. 44.1 MW
View answer and explanation
Correct Option: A
P = η ρ g Q H = 0.9 × 1000 × 9.81 × 10 × 50 = 4.41 × 10⁶ W.
Q130Mechanical Engineering (SSC JE)
Easy
The dryness fraction of dry saturated steam is
A. 0
B. 1
C. greater than 1
D. 0.5
View answer and explanation
Correct Option: B
The dryness fraction x is the mass of dry vapour divided by the total mass. It is 1 for dry saturated steam and 0 for saturated liquid.
Q131Mechanical Engineering (SSC JE)
Easy
A riser in a casting mould is provided to
A. allow the pattern to be withdrawn
B. cool the casting faster
C. increase the mould strength
D. feed molten metal to the casting as it shrinks on solidification
View answer and explanation
Correct Option: D
The riser is the last part to solidify and supplies liquid metal, which prevents shrinkage cavities in the casting.
Q132Mechanical Engineering (SSC JE)
Easy
The shrinkage allowance is given on a pattern so that
A. the mould cavity is sealed
B. the pattern can be easily removed from the mould
C. the casting has the correct size after it cools
D. the casting is made lighter
View answer and explanation
Correct Option: C
The pattern is made slightly larger than the finished casting to offset the contraction of metal during cooling.
Q133Mechanical Engineering (SSC JE)
Easy
TIG welding uses a non-consumable electrode made of
A. copper
B. mild steel
C. aluminium
D. tungsten
View answer and explanation
Correct Option: D
Tungsten has a very high melting point. An inert gas such as argon protects the weld pool.
Q134Mechanical Engineering (SSC JE)
Hard
A workpiece of 50 mm diameter turns at 400 rpm on a lathe. The cutting speed is about
A. 20 m/min
B. 125.7 m/min
C. 6.28 m/min
D. 62.8 m/min
View answer and explanation
Correct Option: D
V = πDN/1000 = π × 50 × 400 / 1000 = 62.8 m/min.
Q135Mechanical Engineering (SSC JE)
Medium
In up milling (conventional milling), the chip thickness is
A. maximum at the start and zero at the end
B. zero at the start of the cut and maximum at the end
C. zero throughout the cut
D. constant throughout the cut
View answer and explanation
Correct Option: B
The cutter rotates against the feed, so each tooth starts with a thin chip that thickens as it leaves the work.
Q136Mechanical Engineering (SSC JE)
Easy
Hot working of metals is done above
A. the eutectic temperature
B. the melting temperature
C. the room temperature
D. the recrystallisation temperature
View answer and explanation
Correct Option: D
Above this temperature, new strain-free grains form as the metal is deformed, so it does not strain harden.
Q137Mechanical Engineering (SSC JE)
Easy
In blanking, the piece punched out of the sheet is
A. the scrap
B. the required product
C. a lubricant
D. the die
View answer and explanation
Correct Option: B
In punching, by contrast, the punched piece is waste and the sheet with holes is the product.
Q138Mechanical Engineering (SSC JE)
Easy
Cold working a metal generally
A. melts the grain boundaries
B. decreases its strength
C. increases its strength and hardness and decreases its ductility
D. increases its ductility
View answer and explanation
Correct Option: C
Strain hardening raises the yield strength but exhausts the ability of the metal to deform further.
Q139Mechanical Engineering (SSC JE)
Easy
Taylor’s tool life equation is
A. V / T = C
B. V = C Tⁿ
C. V + T = C
D. V Tⁿ = C
View answer and explanation
Correct Option: D
V is the cutting speed, T the tool life and n and C are constants for the tool and work material.
Q140Mechanical Engineering (SSC JE)
Easy
Case hardening is done to obtain
A. a hard surface with a tough core
B. a soft surface with a hard core
C. a uniformly hard component
D. a uniformly soft component
View answer and explanation
Correct Option: A
Carburising, nitriding or cyaniding adds hardness to the surface layer of a low carbon steel part.
Q141Mechanical Engineering (SSC JE)
Easy
Sintering in powder metallurgy is
A. melting the powder completely
B. pressing the powder in a die
C. blending the powders
D. heating the compacted powder below its melting point to bond the particles
View answer and explanation
Correct Option: D
Atoms diffuse across particle contacts at high temperature, which gives strength to the compact.
Q142Mechanical Engineering (SSC JE)
Easy
Increasing the rake angle of a cutting tool generally
A. makes the tool more brittle and stronger
B. increases the cutting force
C. reduces the cutting force
D. has no effect on the cutting force
View answer and explanation
Correct Option: C
A larger rake angle shears the chip more easily, but a very large angle weakens the cutting edge.
Q143Mechanical Engineering (SSC JE)
Easy
The angle of friction is equal to
A. the angle of contact
B. twice the angle of repose
C. the angle of repose
D. the angle of incidence
View answer and explanation
Correct Option: C
tan φ = μ, and the angle of repose, at which a body is just about to slide, has the same value.
Q144Mechanical Engineering (SSC JE)
Easy
A body of mass 2 kg moves at 4 m/s. Its kinetic energy is
A. 8 J
B. 4 J
C. 16 J
D. 32 J
View answer and explanation
Correct Option: C
KE = ½mv² = 0.5 × 2 × 16 = 16 J.
Q145Mechanical Engineering (SSC JE)
Easy
The centre of gravity of a triangle from its base is at a distance of
A. one-half of its height
B. one-third of its height
C. one-fourth of its height
D. two-thirds of its height
View answer and explanation
Correct Option: B
The centroid lies at the intersection of the medians, at h/3 from the base.
Q146Mechanical Engineering (SSC JE)
Easy
A projectile has the maximum horizontal range on level ground when its angle of projection is
A. 30°
B. 45°
C. 60°
D. 90°
View answer and explanation
Correct Option: B
R = u² sin 2θ / g is largest when sin 2θ = 1, that is, θ = 45°.
Q147Mechanical Engineering (SSC JE)
Easy
In a vernier caliper, 50 vernier divisions coincide with 49 main scale divisions, and one main scale division is 1 mm. The least count is
A. 0.02 mm
B. 0.05 mm
C. 0.1 mm
D. 0.01 mm
View answer and explanation
Correct Option: A
LC = 1 MSD − 1 VSD = 1 − 49/50 = 0.02 mm.
Q148Mechanical Engineering (SSC JE)
Easy
In limits and fits, tolerance is
A. the difference between the upper and lower limits of a dimension
B. the difference between the sizes of mating parts
C. the clearance between two parts
D. the nominal size of a part
View answer and explanation
Correct Option: A
It is the permissible variation in a dimension, whereas allowance is the intended difference between mating parts.
Q149Mechanical Engineering (SSC JE)
Medium
The Economic Order Quantity (EOQ) is given by
A. 2DS / H
B. √(DS / 2H)
C. √(2DS / H)
D. √(2H / DS)
View answer and explanation
Correct Option: C
D is annual demand, S the ordering cost per order and H the holding cost per unit per year.
Q150Mechanical Engineering (SSC JE)
Easy
Stainless steel contains a minimum chromium content of about
A. 11 percent
B. 5 percent
C. 25 percent
D. 2 percent
View answer and explanation
Correct Option: A
About 10.5 to 11 percent chromium forms a thin self-healing chromium oxide layer, which resists corrosion.

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