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SSC Junior Engineer Exam Paper – 2018 “held on 24 January 2018” Morning Shift (Mechanical Engineering)
Q 1: What kind of contact can be established for a lower pair?
Options:
1) Point contact
2) Surface contact
3) No contact
4) None of these
Answer: Surface contact
Q 2: How many degrees of rotational freedom exists in a free body in space ?
Options:
1) 3
2) 4
3) 5
4) 6
Answer: 3
Q 3: Kinematic chain is known as mechanism when _________.
Options:
1) none of the link is fixed
2) one link is fixed
3) two links are fixed
4) all of the links are fixed
Answer: one link is fixed
Q 4: Which of the following is TRUE for a flywheel which is retarding, if T is the torque on the crankshaft at any instant and Tmean is the mean resisting torque?
Options:
1) Tmean-T>0
2) T -Tmean >0
3) Tmean-T<0
4) T -Tmean <0
Answer: T -Tmean <0
Q 5: Which term defines the fluctuation of speed of a flywheel in terms of linear speeds?
Options:
1) 2(v1 – v2) / (v1 + v2)
2) 2(v1 + v2) / (v1 – v2)
3) v1 + v2 / 2(v1 – v2)
4) v1 – v2 / 2(v1 + v2)
Answer: 2(v1 – v2) / (v1 + v2)
Q 6: What is the velocity ratio for creep in the belt drive system for σ1 being the stress in tight side, σ2 being the stress on slack side and E is the young’s modulus of elasticity of the belt material ?
Options:
1) 
2)
3)
4)
Answer:
Q 7: Which kind of pair can attachment of a car mirror be classified into?
Options:
1) Rolling pair
2) Sliding pair
3) Spherical pair
4) Screw pair
Answer: Sliding pair
Q 8: Which of the following can said to be equivalent with the frictional torque transmitted by a cone clutch?
Options:
1) Flat pivot bearing
2) Flat collar bearing
3) Conical pivot bearing
4) Trapezoidal pivot bearing
Answer: Trapezoidal pivot bearing
Q 9: Which equation represents the frictional torque transmitted in a conical pivot bearing with radius R of shaft and α as the semi-angle of the cone ?
Options:
1) 1/2 x μ.W.R cosec α
2) 2/3 x μ.W.R cosec α
3) 3/4 x μ.W.R cosec α
4) μ.W.R cosec α
Answer: 1/2 x μ.W.R cosec α
Q 10: How the normal pitch (PN) and axial pitch (PC) related to a helical gear with helix angle α ?
Options:
1) PC = PN·cos α
2) PC = PN / cos α
3) PN = PC·cos α
4) PN = PC / cos α
Answer: PC = PN / cos α
Q 11: Which of the following is CORRECT for the train value of a gear train?
Options:
1) Speed of driver/speed of driven
2) Speed of driven/speed of driver
3) Number of teeth on driven/number of teeth on driver
4) None of these
Answer: Speed of driven/speed of driver
Q 12: What will be the change in the vertical height (in m) of a watt governor, when the speed is decreased from 50 rpm to 25 rpm?
Options:
1) 0.358
2) 1.074
3) 1.432
4) 1.79
Answer: 1.074
Q 13: How is sensitivity and stability related to governor?
Options:
1) Directly proportional
2) Inversely proportional
3) Not related
4) Cannot be determined
Answer: Inversely proportional
Q 14: Which ratio defines the height of a watt governor to that of the porter governor for equal arm and link lengths, where m is the mass of the ball and M is the mass of the sleeve?
Options:
1) m / (M + m)
2) M / (M + m)
3) (M + m) / m
4) (M + m) / M
Answer: m / (M + m)
Q 15: Which of the following cam follower has the highest wear rate?
Options:
1) Knife edge follower
2) Roller follower
3) Flat face follower
4) Spherical faced follower
Answer: Knife edge follower
Q 16: When the friction comes into action between the two running parts of a machine, it results in the production of ________.
Options:
1) light
2) oil
3) energy
4) heat
Answer: heat
Q 17: When the position of the body is either in rest or in uniform velocity, then the body is said to be in the ________.
Options:
1) rest
2) uniform motion
3) rotational motion
4) equilibrium
Answer: equilibrium
Q 18: The beam which has one ________ end and other ________ end is known as cantilever beam.
Options:
1) fixed, free
2) fixed, hinged
3) hinged, free
4) None of these
Answer: fixed, free
Q 19: Calculate the value of modulus of rigidity (N/mm2) if the Poisson’s ratio is 0.25 and modulus of elasticity for the material is 200 N/mm2?
Options:
1) 50
2) 80
3) 100
4) 150
Answer: 80
Q 20: Choose the INCORRECT option for the Hooke’s law.
Options:
1)
2)
3)
4) and both
Answer: and both
Q 21: A steel rod whose diameter is 2 cm and is 2 m long, experiences heating of temperature 30oC to 150oC. The coefficient of thermal expansion is α = 12 x 10-6 / oC and Young’s modulus is 200 GPa. If the rod has been restricted to its original position, then the thermal stress (MPa) developed will be ________.
Options:
1) 234
2) 256
3) 288
4) 300
Answer: 288
Q 22: The conditions for the thermal stress in a body are given below.
(1) It is the function of coefficient of thermal expansion.
(2) It is the function of temperature rise.
(3) It is the function of modulus of elasticity.
Which of the following is the CORRECT answer?
Options:
1) 1 and 2 only
2) 1 and 3 only
3) 2 and 3 only
4) All option are correct
Answer: All option are correct
Q 23: If the stress acting on a point is in the three dimensions, then what is the number of components in a stress tensor required for defining that stress?
Options:
1) 3
2) 4
3) 6
4) 9
Answer: 9
Q 24: If the equivalent torque in a shaft is 500 Nm and the bending moment is 300 Nm. Calculate the magnitude of the required torque and the equivalent bending moment.
Options:
1) 500 Nm and 400 Nm
2) 400 Nm and 400 Nm
3) 400 Nm and 500 Nm
4) 300 Nm and 400 Nm
Answer: 400 Nm and 400 Nm
Q 25: What will be the change in length (mm) of a steel bar having a square cross section of dimension 40 mm x 40 mm, which is subjected to an axial compressive load of 250 kN. If the length of the bar is 4 m and modulus of elasticity is E = 250 GPa?
Options:
1) 2.5
2) 1.25
3) 2
4) 1.5
Answer: 2.5
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Q 26: Choose the INCORRECT option for the equation of elongation of a uniform rod having length L due to the self weight W.
Options:
1) δ = WL / 2AE
2) δ = 2WL / AE
3) δ = WL / AE
4) δ = 2WL / AE and δ = WL / AE both
Answer: δ = 2WL / AE and δ = WL / AE both
Q 27: Consider the loaded beam as shown in the figure below. Determine the portion of the beam which is subjected to pure bending.
Options:
1) DE
2) CD
3) BD
4) AE
Answer: BD
Q 28: Calculate the total angle of twist for a stepped shaft which is subjected to the torque (T) as shown in the figure below.
Options:
1) TI / πGd4
2) 66TI / πGd4
3) TI / 66Gd4
4) 36TI / πGd4
Answer: 36TI / πGd4
Q 29: A cross sectional bar of area 700 mm2 is subjected to an axial load as shown in the figure below. What is the value of stress (MPa) in the section RS?
Options:
1) 30
2) 40
3) 50
4) 60
Answer: 30
Q 30: If the diameter of the column is reduced by 30%, then what will be the change in the Euler’s buckling load (in %)?
Options:
1) 25
2) 50
3) 75
4) 100
Answer: 75
Q 31: What is the value of latent heat of vapourization at critical point?
Options:
1) Zero
2) Greater than zero
3) Less than zero
4) Insufficient data
Answer: Zero
Q 32: What happens to the specific volume of water when it is heated at 0oC?
Options:
1) Decreases steadily
2) Increases steadily
3) First increases then decreases
4) First decreases then increases
Answer: First decreases then increases
Q 33: Which of the following is the other name of isentropic process?
Options:
1) a reversible isothermal process
2) a reversible adiabatic process
3) a reversible isobaric process
4) a reversible isochoric process
Answer: a reversible adiabatic process
Q 34: Which of the following represents an impossible cycle?
Options:
1)
2)
3)
4) None of these
Answer:
Q 35: Which of the following is INCORRECT for reversible adiabatic process?
Options:
1) dS=0
2) S is constant.
3) dQ=0
4) Q is not constant.
Answer: Q is not constant.
Q 36: Which of the following method of fuel ignition is used in diesel engine?
Options:
1) Spark plug
2) Fuel injector
3) Combustion chamber
4) Heat from compressed air
Answer: Heat from compressed air
Q 37: How self ignition temperature of petrol be compared to that of diesel?
Options:
1) Higher
2) Lower
3) Same
4) Insufficient data
Answer: Higher
Q 38: Which of the following is TRUE for supercharging?
Options:
1) Supplying higher density of air at intake than the surrounding.
2) Providing forced cool air at intake.
3) Raising exhaust pressure
4) Supplying excess fuel for raising load
Answer: Supplying higher density of air at intake than the surrounding.
Q 39: Which term best represents the calorific value of gaseous fuel?
Options:
1) kcal
2) kcal/kg
3) kcal/m2
4) kcal/n
Answer: kcal/kg
Q 40: Which of the substance can be classified as pure substance?
Options:
1) Humid air
2) Soil
3) Sand in water
4) Baking soda
Answer: Baking soda
Q 41: Which of the following statement is INCORRECT for work output of an ideal Otto cycle?
Options:
1) Decreases with an increase in adiabatic index.
2) Decreases with an increase in compression ratio.
3) Increases with an increase in pressure ratio.
4) Both Decreases with an increase in adiabatic index and Decreases with an increase in compression ratio.
Answer: Both Decreases with an increase in adiabatic index and Decreases with an increase in compression ratio.
Q 42: A reversible engine, which operates between temperature range of 1200 K and 600 K, rejects 30% of heat to the sink comes under the classification of?
Options:
1) Carnot Engine
2) Petrol engine
3) Diesel engine
4) None of these
Answer: None of these
Q 43: Which relation clearly depicts the absolute thermodynamic temperature scale?
Options:
1) Q1 / Q2 = T1 / T2
2) Q2 / Q1 = T1 / T2
3) Q1 / Q2 = T1 / T2 and Q2 / Q1 = T1 / T2 both
4) None of these
Answer: Q1 / Q2 = T1 / T2
Q 44: At triple point for water, which of the following term is not equal to zero?
Options:
1) Enthalpy
2) Entropy
3) Internal energy
4) None of these
Answer: Enthalpy
Q 45: What does the term ‘quality’ indicate?
Options:
1) Mass fraction of liquid in a liquid vapour mixture
2) Mass fraction of vapour in a liquid vapour mixture
3) Both Mass fraction of liquid in a liquid vapour mixture and Mass fraction of vapour in a liquid vapour mixture
4) None of these
Answer: Mass fraction of vapour in a liquid vapour mixture
Q 46: A gas is compressed frictionless from an initial state of y m3 and 1 MPa to a final state of 0.2 m3 and 1 MPa. There is a transfer of 40 kJ of heat from the gas and a drop of 20kJ in internal energy. What is the initial state volume of the gas?
Options:
1) 0.2
2) 0.22
3) 19.8
4) 20.2
Answer: 0.22
Q 47: What is the drop in enthalpy (in kJ/kg) for a steam whistle which is perfectly insulated and does not work has an exit velocity of steam at 40 m/sec?
Options:
1) 0.8
2) 8
3) 80
4) 800
Answer: 0.8
Q 48: Two Carnot engines are connected in a series with working extreme temperatures as 2000 K and 200 K respectively. What is the efficiency of the first Carnot engine (in %)?
Options:
1) 0
2) 50
3) 68
4) 90
Answer: 0
Q 49: What the region (3) in the p-V diagram given below is called ?
Options:
1) Compressed liquid region
2) Saturated liquid vapour region
3) Solid-liquid region
4) Superheated region
Answer: Saturated liquid vapour region
Q 50: Which formula is the CORRECT depiction of slope of adiabatic curve?
Options:
1) dP / dV = -γ(P/V)
2) dP / dV = P/V
3) dP / dV = -(P/V)
4) dP / dV = γ(P/V)
Answer:
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Q 51: ______ surface hardening process gives maximum hardness to the surface.
Options:
1) Pack hardening
2) Nitriding
3) Cyaniding
4) Induction hardening
Answer: Nitriding
Q 52: ______ is not a ceramic material
Options:
1) Glass
2) Bakelite
3) Clay
4) Aluminium oxide
Answer: Bakelite
Q 53: To which of the following is the proof stress related?
Options:
1) Elongation
2) Necking
3) Yielding
4) Fracture
Answer: Elongation
Q 54: Mechanical seals are used
Options:
1) to prevent vibrations
2) to prevent leakage
3) to reduce friction
4) to balance the equipment
Answer: to prevent leakage
Q 55: Noise level in case of an aircraft is
Options:
1) generally less than 100 db
2) generally more than 100 db
3) always more than 100 db
4) in the range of 60-80 db
Answer: always more than 100 db
Q 56: The tool life of a tool is said to be over if
Options:
1) the tool has failed and a poor surface finish is obtained
2) sudden increase in power and cutting forces takes place and chatter appears in machining
3) overheating and fuming due to friction occurs in addition to dimensional instability
4) All option are correct
Answer: All option are correct
Q 57: Graphite moulds are generally used for continuous casting method because
Options:
1) the metals wet the mould slightly
2) only a small film of lubricating oil is required
3) they are self-lubricating
4) they are comparatively cheaper
Answer: they are self-lubricating
Q 58: Ceramic tools are fixed to tool by the following process
Options:
1) soldering
2) brazing
3) welding
4) clamping
Answer: brazing
Q 59: Gear tooth Vernier is used
Options:
1) to measure the addendum
2) to measure the addendum and dedendum
3) to measure the circular pitch
4) to measure the pitch line thickness of both
Answer: to measure the pitch line thickness of both
Q 60: Which one of the following is the steady flow energy equation for a boiler ?
Options:
1) A only
2) B only
3) C only
4) D only
Answer:D only
Q 61: The major constituents of a fuel are
Options:
1) carbon, hydrogen and oxygen
2) carbon, hydrogen, oxygen and nitrogen
3) carbon, oxygen, hydrogen, nitrogen, phosphorus and sulphur
4) Carbon and hydrogen
Answer: Carbon and hydrogen
Q 62: The general gas equation is given as
Options:
1) pv = mT
2) p/V=mT
3) pT =mRT
4) p/V = mRT
Answer: pT =mRT
Q 63: Molar volume is equal to
Options:
1) 22.41 m3 at NTP
2) 2.241 m3 at NTP
3) 29.27 m3 at NTP
4) 1.03 m3 at NTP
Answer: 22.41 m3 at NTP
Q 64: Internal combustion engine works on
Options:
1) first law of thermodynamics
2) second law of thermodynamics
3) zeroth law of thermodynamics
4) None of these
Answer: first law of thermodynamics
Q 65: The first and second laws of thermodynamics help to derive the following properties, respectively.
Options:
1) pressure and temperature
2) temperature and entropy
3) pressure and entropy
4) temperature and enthalpy
Answer: temperature and entropy
Q 66: Constant volume process is
Options:
1) isopiestic process
2) hyperbolic process
3) isometric process
4) polytropic process
Answer: isometric process
Q 67: Stream and velocity potential functions for a two-dimensional flow field given by u = 2x and v = -2y are
a) Ψ = 2xy, φ = x2 – y2
b) Ψ = x2 – y2 , φ = 2xy
c) Ψ = x2 y2, φ = x2 + y2
d) Ψ = x2 + y2, φ = x2 y2
Options:
1) (a) Only
2) (b) Only
3) (c ) Only
4) (d) Only
Answer: (b) Only
Q 68: The internal energy of a gas obeying van der Waals, equation (p + a/V2)(V-b)= RT depends on its
Options:
1) temperature
2) temperature and pressure
3) temperature and specific volume
4) pressure and specific volume
Answer: temperature and specific volume
Q 69: Consider the following properties:
(1) Entropy
(2) Viscosity
(3) Temperature
(4) Specific heat at constant volume
Which of the above properties of a system is/are extensive?
Options:
1) Only 1
2) Only 1 and 2
3) Only 2, 3 and 4
4) Only 1, 2 and 4
Answer: Only 1
Q 70: In cooling tower, water is cooled by the process of:
Options:
1) condensation
2) fusion
3) evaporation
4) sublimation
Answer: evaporation
Q 71: While starting the centrifugal pump
Options:
1) delivery valve is kept wide open
2) delivery valve is kept closed
3) inlet valve is kept closed
4) delivery valve is opened slightly
Answer: delivery valve is kept closed
Q 72: In the centrifugal pump, maximum efficiency is obtained when the blades are
Options:
1) bent backward
2) bent forward
3) straight
4) berit to have aerofoil section
Answer: straight
Q 73: One dimension flow is one
Options:
1) involving zero transverse components of flow
2) in uniform flow
3) in steady uniform flow
4) None of these
Answer: involving zero transverse components of flow
Q 74: The hydraulic mean depth for a rectangular section is: Where, b = Width of rectangular section d = Depth of water
Options:
1) bd / (2d+b)
2) bd / (d+b)
3) 2bd / (d+b)
4) bd / 2(d+b)
Answer: bd / (2d+b)
Q 75: The branch of Engineering Science, which deals with water at rest or in motion is called
Options:
1) hydraulics
2) fluid mechanics
3) applied mechanics
4) kinematics
Answer: hydraulics
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Q 76: Pressure inside a water droplet is given by the relation
Options:
1) ρ=4σ/d
2) ρ=3σ/d
3) ρ=8σ/d
4) ρ=16σ/d
Answer: ρ=4σ/d
Q 77: Vertical distribution of velocity in an open channel for laminar flow can be assumed as
Options:
1) offer no resistance to change of shape
2) offer resistance to change of shape
3) offer least resistance to compression
4) None of these
Answer: offer least resistance to compression
Q 78: A manometer is used to measure
Options:
1) velocity of flow in channel
2) atmospheric pressure
3) pressure in pipes
4) None of these
Answer: pressure in pipes
Q 79: The length of mouthpiece as-compared to diameter is
Options:
1) 5 to 6 times
2) 6 to 8 times
3) 2 to 3 times
4) 1 to 1.5 times
Answer: 2 to 3 times
Q 80: The lower critical Reynolds number is approximately equal to
Options:
1) 100
2) 200
3) 1000
4) 2000
Answer: 2000
Q 81: If a thin plate is held normal to the flow, the viscous drag on it is
Options:
1) maximum
2) minimum
3) zero
4) None of these
Answer: zero
Q 82: The cross section of cippoletti weir is
Options:
1) rectangular
2) triangular
3) trapezoidal
4) None of these
Answer: trapezoidal
Q 83: When there is no air left blow the nappe, it is known as
Options:
1) free nappe
2) depressed nappe
3) adhering nappe
4) All option are correct
Answer: adhering nappe
Q 84: In case of reaction turbine
Options:
1) P1 = P2
2) P1 > P2
3) P1 < P2
4) None of these
Answer: P1 > P2
Q 85: The overall efficiency of Pelton wheel is about
Options:
1) 0.55
2) 0.65
3) 0.85
4) 0.99
Answer: 0.85
Q 86: If α is the rake angle of the cutting tool, Ψ is the shear angle and ϑ is the cutting velocity, then the velocity of chip sliding along the shear plane is given by
a) ϑcos α / sin(Ψ – α)
b) ϑsin α / sin(Ψ – α)
c) ϑsin α / cos(Ψ – α)
d) ϑcos α / cos(Ψ – α)
Options:
1) (a)
2) (b)
3) (c )
4) (d)
Answer: (a)
Q 87: Which one of the statements is correct for a forced vortex?
Options:
1) Turns in an opposite direction to a free vortex
2) Always occurs in conjunction with a free vortex
3) Has the linear velocity directly proportional to the radius
4) Has the linear velocity inversely proportional to the radius
Answer: Has the linear velocity directly proportional to the radius
Q 88: Why is multi-staging in centrifugal pumps used?
Options:
1) For high flow rate
2) For high head
3) For high speed
4) For high efficiency
Answer: For high head
Q 89: The overall efficiency of a Pelton turbine is 70%. If the mechanical efficiency is 85%, what is its hydraulic efficiency?
Options:
1) 0.824
2) 0.595
3) 0.723
4) 0.815
Answer: 0.824
Q 90: Which of the following water turbines does not require a draft tube?
Options:
1) Propeller turbine
2) Pelton Turbine
3) Kaplan turbine
4) Francis turbine
Answer: Pelton Turbine
Q 91: Which phenomenon will occur when the value at the discharge end of a pipe connected to a reservoir is suddenly closed?
Options:
1) Cavitation
2) Erosion
3) Hammering
4) Surging
Answer: Hammering
Q 92: The pressure drop for a relatively low Reynolds number flow in a 600 mm, 30 m long pipeline is 70 kPa. What is the wall shear stress?
Options:
1) 0
2) 350 Pa
3) 700 Pa
4) 1400 Pa
Answer: 350 Pa
Q 93: Uniform flow occurs when
Options:
1) the flow is steady
2) the flow is streamline
3) size and shape of the cross section in a particular length remain constant
4) size and cross section change uniformly along length
Answer: size and shape of the cross section in a particular length remain constant
Q 94: General energy equation holds for
Options:
1) steady flow
2) turbulent flow
3) laminar flow
4) non-uniform flow
Answer: non-uniform flow
Q 95: Two pipe systems can be said to be equivalent, when the following quantities are same
Options:
1) friction loss and flow
2) length and diameter
3) flow and length
4) friction factor and diameter
Answer: friction loss and flow
Q 96: Water, by evaporative cooling, can theoretically be cooled down to:-
Options:
1) atmospheric temperature
2) air’s dry bulb temperature
3) air’s wet bulb temperature
4) air’s dew point temperature
Answer: air’s dew point temperature
Q 97: Any change in load is adjusted by adjusting following parameter on turbine
Options:
1) net head
2) absolute velocity
3) blade velocity
4) flow
Answer: flow
Q 98: A turbine pump is basically a centrifugal pump equipped additionally with
Options:
1) adjustable blades
2) backward curved blades
3) vaned diffusion casing
4) inlet guide blades
Answer: vaned diffusion casing
Q 99: A Pelton wheel is
Options:
1) impulse turbine
2) radial flow impulse turbine
3) inward flow impulse turbine
4) outward flow impulse turbine
Answer: impulse turbine
Q 100: Guide angle as per the aerofoil theory of Kaplan turbine blade design is defined as the angle between
Options:
1) lift and resultant force
2) drag and resultant force
3) lift and tangential force
4) lift and drag
Answer: lift and resultant force
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