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# SSC Junior Engineer Exam Paper 2017 Shift-3 (Mechanical Engineering)

SSC Junior Engineer Exam Paper – 2016 “held on 02 March 2017 “Morning Shift (General Engineering)

Q 1: A football was inflated to a gauge pressure of 1 bar when the ambient temperature was 15°C. When the game started next day, the air temperature at the stadium was 5°C. Assume that the volume of the football remains constant at 2500 cm3. Gauge pressure of air to which the ball must have been originally inflated so that it would equal 1 bar gauge at the stadium is _____.

Options:
1) 2.23 bar
2) 1.94 bar
3) 1.07 bar
4) 1 bar

Q 2: The engine oil at 150 °C is cooled to 80 °C in a parallel flow heat exchanger by water entering at 25 °C and leaving at 60 °C. The exchanger effectiveness will be _____.

Options:
1) 0.36
2) 0.46
3) 0.56
4) 0.66

Q 3: The atomic packing factor is the highest in which of the following cubic lattice system?
Options:
1) Simple Cubic
2) Body Centered Cubic (BCC)
3) Face Centered Cubic (FCC)
4) Diamond Cubic

Q 4: The valves mounted on the boilers which change the direction of flow of steam by 90° and valves fitted in the pipelines which allow the steam in the same direction are respectively called as _____.
Options:
1) Stop valves and junction valves
2) Junction valves and stop valves
3) Junction valves and safety valves
4) Feed safety valves and stop valves

Answer: Junction valves and stop valves

Q 5: Which of the following are boiler mountings and not boiler accessories ?

A] Pressure gauge
B] Air preheater
C] Superheater
Options:
1) B and C only
2) A only
3) A, B and C
4) A and C only

Q 6: Entropy is a measure of _____.

Options:
1) Reversible heat transfer
2) System efficiency
3) Degree of randomness
4) System temperature

Q 7: Gibbs free energy is considered at which one of the following condition?

Options:
1) Isothermal, isochoric
2) Isobaric, isochoric
3) Isothermal, isobaric
4) None of these

Q 8: In vapour absorption refrigeration systems, which of the following fluids are commonly used?

Options:
1) air and water
2) sulphur dioxide and water
3) ammonia and water
4) freon and water

Q 9: In a cross compound steam engine _____.
Options:
1) one high and one low pressure cylinder are set side by side, driving the same shaft, cranks being set 90° apart
2) two cylinders are centred on the same piston rod, the 1.p. cylinder being placed nearest the crankshaft
3) two cylinders are set at 90°, usually to save floor space
4) None of these

Answer: two cylinders are centred on the same piston rod, the 1.p. cylinder being placed nearest the crankshaft

Q 10: Which of the following is expected to have highest thermal conductivity?

Options:
1) steam
2) solid ice
3) melting ice
4) water

Q 11: A reversible thermodynamic cycle containing only three processes and producing work is to be constructed. The constraints are

1. there must be one isothermal process
B. there must be one isentropic process
C. maximum and minimum cycle pressures and the clearance volume are fixed, and
D. polytropic processes are not followed Then, the number of possible cycles is

Options:
1) 1
2) 2
3) 3
4) 4

Q 12: Which combination of the following statements is correct?
The incorporation of re-heater in a steam power plant
A. Always increases the thermal efficiency of the plant
B. Always increases the dryness fraction of steam at condenser inlet
C. Always increases the main temperature of heat addition
D. Always increases the specific work output
Options:
1) A and D only
2) B and D only
3) A, C and D only
4) A, B, C and D

Answer: A, B, C and D

Q 13: The amount of heat required to raise the temperature of 1 kg of water from 0°C to the saturation temperature Ts °C at a given constant pressure is defined as _____.

Options:
1) Superheat
2) Entropy
3) Latent heat
4) Sensible heat

Q 14: The enthalpy of steam is defined as _____.
Options:
1) Difference of internal energy and product of pressure and volume.
2) Product of internal energy and pressure.
3) Sum of internal energy and product of pressure and volume.
4) Amount of heat change divided by the absolute temperature.

Answer: Sum of internal energy and product of pressure and volume.

Q 15: What are the advantages of water tube boilers over fire tube boilers?
A. Steam at higher pressures can be produced.
B. More effective heat transfer.
C. Sediment deposition is more.
Options:
1) A only
2) A and C only
3) A, B and C
4) A and B only

Q 16: What is the state, in which none of the properties of the system change with time, known as?

Options:
3) Dynamic
4) Quasistatic

Q 17: The rate of heat transfer across any plane normal to the x-direction is proportional to the wall area and the temperature gradient in the x-direction. This statement is also referred to as _____.
Options:
1
) Second Law of Thermodynamics

2) Kelvin’s Law
3) Third Law of Thermodynamics
4) Fourier’s Law

Q 18: The critical temperature of a pure substance is defined as _____

Options:
1) The minimum temperature at which solid and liquid phases can coexist in equilibrium.
2) The maximum temperature at which solid and liquid phases can coexist in equilibrium.
3) The minimum temperature at which vapour and liquid phases can coexist in equilibrium.
4) The maximum temperature at which vapour and liquid phases can coexist in equilibrium.

Answer: The maximum temperature at which vapour and liquid phases can coexist in equilibrium.

Q 19: Which of the following is the correct expression for the maximum thermal efficiency (η) of a system undergoing a reversible power cycle while operating between thermal reservoirs at temperatures Tc and Th

Options:
1) η = Tc/Th
2) η = Th/Tc-1
3) η = 1-Tc/Th
4) η = 1

Q 20: In actual refrigeration systems, the compressor handles vapour only. What is this process commonly referred to as _____.

Options:
1) Gas compression
2) Phase compression
3) Dry compression
4) Wet compression

Q 21: Property of a fluid at zero temperature is referred to as _____.

Options:
1) Stagnation property
2) Standard property
3) Simple property
4) None of these

Q 22: The increase in pressure _____.

Options:
1) lowers the boiling point of a liquid
2) raises the boiling point of a liquid
3) does not affect the boiling point of a liquid
4) reduces its volume

Answer: raises the boiling point of a liquid

Q 23: The overall efficiency of thermal power plant is _____.

Options:
1) Boiler efficiency, turbine efficiency and generator efficiency
2) Boiler efficiency, turbine efficiency, generator efficiency and gas cycle efficiency
3) Carnot cycle efficiency
4) Regenerative cycle efficiency

Answer: Boiler efficiency, turbine efficiency and generator efficiency

Q 24: Heat transfer by radiation mainly depends upon _____.

Options:
1) its temperature
2) nature of the body
3) kind and extent of its surface
4) All optons are correct

Q 25: Thermal diffusivity is _____.

Options:
1) a dimensionless parameter
2) function of temperature
3) used as mathematical model
4) a physical property of the material

Answer: a physical property of the material

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Q 26: Condensing temperature in a refrigerator is the temperature _____.

Options:
1) of cooling medium
2) of freezing zone
3) of evaporator
4) at which refrigerant gas becomes liquid

Answer: at which refrigerant gas becomes liquid

Q 27: With an increase in the thickness of insulation around a circular pipe, heat loss to surroundings due to _____.

Options:
1) convection increases, where as due to conduction decreases
2) convection decreases, where as due to conduction increases
3) both convection and conduction decreases
4) both convection and conduction increases

Answer: convection increases, where as due to conduction decreases

Q 28: For air with a relative humidity of 80% _____.

Options:
1) dry bulb temperature is less than the wet bulb temperature
2) dew point temperature is less than wet bulb temperature
3) dew point and wet bulb temperatures are equal
4) dry bulb and dew point temperatures are equal

Answer: dew point temperature is less than wet bulb temperature

Q 29: If a mass of moist air in an airtight vessel is heated to a higher temperature, then _____.

Options:
1) specific humidity of the air increases
2) specific humidity of the air decreases
3) relative humidity of the air increases
4) relative humidity of the air decreases

Answer: relative humidity of the air decreases

Q 30: In a vapour compression refrigeration system, liquid to suction heat exchanger is used to _____.

Options:
1) keep the COP constant
2) prevent the liquid refrigerant from entering the compressor
3) sub-cool the liquid refrigerant leaving the condenser
4) sub-cool the vapour refrigerant from the evaporator

Answer: sub-cool the liquid refrigerant leaving the condenser

Q 31: A right-circular cylinder open at top is filled with water and rotated about its vertical axis at such speed that half the water spills out. What is the value of pressure at centre of the bottom?

Options:
1) One half its value when cylinder was full
2) One fourth its value when cylinder was full
3) Zero
4) Insufficient data

Q 32: At a point on a streamline, the velocity is 3 m/sec and the radius of curvature is 9 m. If the rate of increase of velocity along the streamline at this point is 1/3 m/sec/m, then the total acceleration at this point would be _____.

Options:
1) 1 m/sec2
2) 3 m/sec2
3) 1/3 m/sec2
4) √2 m/sec2

Q 33: Which of the following statements is correct regarding an impulse turbine?

Options:
1) The steam is initially compressed in a nozzle from low pressure to high pressure.
2) The steam is initially expanded in a nozzle from low pressure to high pressure.
3) The steam is initially compressed in a nozzle from high pressure to low pressure.
4) The steam is initially expanded in a nozzle from high pressure to low pressure.

Answer: The steam is initially expanded in a nozzle from high pressure to low pressure.

Q 34: A draft tube is used with _____.
Options:
1) impulse turbine
2) Pelton wheel turbine
3) reaction turbines
4) axial turbine pumps

Q 35: For Newtonian fluid behaviour, the shear stress exerted by the fluid is equal to the _____.

Options:
1) Fluid viscosity divided by the velocity gradient parallel to the direction of shear.
2) Fluid viscosity divided by the velocity gradient perpendicular to the direction of shear.
3) Product of the fluid viscosity and the velocity gradient parallel to the direction of shear.
4) Product of the fluid viscosity and the velocity gradient perpendicular to the direction of shear.

Answer: Product of the fluid viscosity and the velocity gradient perpendicular to the direction of shear.

Q 36: Which of the following are the advantages of impulse turbine over reaction turbines ?
A. Occupies less space per unit power.
B. Compounding is not necessary for speed reduction as the rotor speeds are usually low.
C. Suitable for high power generation.
Options:
1) B and C only
2) A only
3) C only
4) A and C only

Q 37: The compressors used in a gas turbine are typically of which type?

Options:
1) Centrifugal
2) Centripetal
3) Reciprocating
4) Axial

Q 38: Which turbine is also called as the propeller turbine?
Options:
1) Kaplan turbine
2) Francis turbine
3) Pelton wheel
4) Thompson turbine

Q 39: According to Bernoulli’s principle in fluid dynamics, for inviscid flow, increase in speed of fluid leads to which of the following?

Options:
1) Increase in pressure and/or increase in fluid’s potential energy
2) Decrease in pressure and/or increase in fluid’s potential energy
3) Increase in pressure and/or decrease in fluid’s potential energy
4) Decrease in pressure and/or decrease in fluid’s potential energy

Answer: Decrease in pressure and/or decrease in fluid’s potential energy

Q 40: The material commonly used for air craft gas turbine is _____.
Options:
1) stainless steel
2) high alloy steel
3) duralumin
4) titanium

Q 41: The difference of absolute pressure and local atmospheric pressure is known as _____.
Options:
1) Negative pressure
2) Positive pressure
3) Gauge pressure
4) Hydraulic pressure

Q 42: The sum of pressure head and elevation head is known as _____.
Options:

Q 43: Specific gravity is defined as the ratio of density of fluid and density of water at which temperature (in °C)?

Options:
1) 0
2) 100
3) 4
4) It is not dependent on temperature

Q 44: Falling drops of water become spheres due to the property of _____.
Options:
2) cohesion
3) surface tension
4) viscosity

Q 45: Fluid flow in a straight circular pipe is typically laminar in nature when the Reynolds number is _____.
Options:
1) Less than 2300
2) Less than 4000
3) More than 2300
4) More than 4000

Q 46: The reduction in fluid pressure that results when a fluid flows through a constricted section of a pipe is known as _____.
Options:
1) Orifice effect
2) Bernoulli’s principle
3) Secondary flow
4) Venturi effect

Q 47: For a compressible flow, Mach Number (M) is given by which of the following expression? where v = velocity of fluid in compressible flow c = speed of sound in air
Options:
1) M = v/√c
2) M = c/v
3) M = v/c
4) M = v/c2

Q 48: Which type of forces dominates a fluid flow with a very high Reynolds Number (Re ≈ 10000)?
Options:
1) Inertial
2) Viscous
3) Reaction
4) Divergent

Q 49: To avoid cavitation in centrifugal pumps _____.
Options:
1) suction pressure should be low
2) delivery pressure should be low
3) suction pressure should be high
4) delivery pressure should be high

Answer: suction pressure should be high

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Q 50: For the continuity equation given by .  = 0 to be valid, where  is the velocity vector, which one of the following is a necessary condition ?
Options:
2) Irrotational flow
3) Inviscid flow
4) Incomprehensible flow

Q 51: Match the items in List 1 and 2.

 List-1 List-2 A Compressible flow 1 Reynolds number B Free surface flow 2 Nusselt number C Boundary layer flow 3 Weber number D Pipe flow 4 Froude Number E Heat Convection 5 Match number 6 Skin friction Coefficient

Options:
1) A-1, B-4, C-2, D-6; E-3
2) A-3, B-4, C-6, D-1; E-2
3) A-5, B-3, C-6, D-1; E-4
4) A-5, B-3, C-6, D-1; E-2

Answer: A-5, B-3, C-6, D-1; E-2

Q 52: Match the items in List 1 and 2.

 List-1 List-2 A Centrifugal compressor 1 Axial flow B Centrifugal Pump 2 Surging C Pelton wheel 3 Priming D Kalpan turbine 4 Pure Impulse

Options:
1) A-2, B-3, C-4, D-1
2) A-2, B-3, C-1, D-4
3) A-3, B-4, C-1, D-2
4) A-1, B-2, C-3, D-4

Q 53: A fluid whose shear stress is linearly proportional to the velocity gradient in the direction perpendicular to the plane of shear is called as _____.
Options:
1) Friction fluid
2) Stress fluid
3) Newtonian fluid
4) Cartesian fluid

Q 54: Euler’s equation for the motion of liquid assumes that _____.
Options:
1) Fluid is viscous
2) Fluid is homogeneous and incompressible
3) Velocity of flow is non-uniform over the section
4) Flow is unsteady along with stream line

Answer: Fluid is homogeneous and incompressible

Q 55: A flow whose stream line is represented by a curve, is called _____.
Options:
1) One-dimensional flow
2) Three dimensional flow
3) Two-dimensional flow
4) Four-dimensional flow

Q 56: The frictional resistance of a pipe varies approximately with _________of the liquid.
Options:
1) pressure
2) square of velocity
3) velocity
4) cube of the velocity

Q 57: The cavitation in a hydraulic machine is mainly due to _____.
Options:
1) Low velocity
2) Low pressure
3) High velocity
4) High pressure

Q 58: The stress, which is responsible for retaining water in a capillary tube above the free water surface of the water body in which the capillary tube is inserted, is called the _____.
Options:
1) Capillary compression
2) Capillary tension
3) Capillary pore pressure
4) None of these

Q 59: A flow whose stream line is represented by a curve, is called _____.
Options:
1) One-dimensional flow
2) Three dimensional flow
3) Two-dimensional flow
4) Four-dimensional flow

Q 60: A single speed centrifugal pump, feeding a small water supply distribution system of a block of houses, works at _____.
Options:

1) Maximum efficiency
2) Minimum efficiency
3) Reduced efficiency
4) None of these

Q 61: In under-damped vibrating system, the amplitude of vibration with reference to time _____.
Options:
1) increases linearly
2) increases exponentially
3) decreases linearly
4) decreases exponentially

Q 62: A three rotor system has following number of natural frequencies _____.
Options:
1) 1
2) 2
3) 3
4) 4

Q 63: The figure given below shows a crusher having several cylindrical rollers of weight W. The crushing force due to each roller will be:

Options:
1) W
2) less than W
3) more than W
4) unpredictable

Q 64: The principle of direct and reverse cranks is readily applicable to _____.
Options:
1) primary balance
2) secondary balance
3) balancing of in-line engines
4) partial primary balance

Q 65: In order to facilitate the starting of locomotive in any position, the cranks of a locomotive with two cylinders are placed at following angle to each other _____.
Options:
1) 45°
2) 90°
3) 135°
4) 180°

Q 66: The critical speed depends on _____.
Options:
1) mass
2) stiffness
3) mass and stiffness
4) mass, stiffness and eccentricity

Q 67: If a more stiff spring is used in Hartnell governor, then the governor will be _____.

Options:
1) more sensitive
2) less sensitive
3) sensitively remains unaffected
4) isochronous

Q 68: A gear having 100 teeth is fixed and another gear having 25 teeth revolves around it, the centre lines of both gears being joined by an arm. How many revolutions will be made by gear of 25 teeth for one revolution of arm?

Options:
1) 4
2) 3
3) 5
4) 6

Q 69: The power transmitted by a belt is maximum when the maximum tension in the belt compared to centrifugal tension is _____.
Options:
1) 2 times
2) 3 times
3) 4 times
4) 2.5 times

Q 70 – A rotating mass having moment of inertia of 30 kgm2 rotates at 800 rpm and is travelling in a curve of 170 metre radius at a speed of 240 km/hr. It will experience a gyroscopic reaction of _____.

Options:
1) 10 m kgf
2) 100 m kgf
3) 1000 m kgf
4) 10000 m kgf

Q 71: Throw of a cam is the maximum distance of the follower from:

Options:
1) Base circle
2) Pitch circle
3) Root circle
4) Prime circle

Q 72: The following is the inversion of slider crank mechanism
A. Whitworth quick return mechanism
B. Hand pump
C. Oscillating cylinder engine
Options:
1) only A
2) only B
3) only C
4) A, B and C

Q 73: The horse power transmitted by a belt is dependent upon
A. tension on tight side of belt
B. tension on slack side of belt
D. speed of pulley
Options:
1) only A and B
2) only B and C
3) only D
4) A, B, C and D

Answer: A, B, C and D

Q 74: Which of the following is a lower pair?
A. Ball and socket
B. Piston and cylinder
C. Cam and follower
Options:
1) only A
2) only B
3) only C
4) A and B

Q 75: The distance between the centres of the rivets in adjacent rows of zigzag riveted joint is known as _____.
Options:
1) pitch
2) back pitch
3) diagonal pitch
4) diametric pitch

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Q 76: A body is resting on a plane inclined at angle 30° to horizontal. What force would be required to slide it down, if the coefficient of friction between body and plane is 0.3?
Options:
1) Zero
2) 1 kg
3) 5 kg
4) None of these

Q 77: A satellite is kept on moving in its orbit around the earth due to _____.

Options:
1) centrifugal force
2) centripetal force
3) gravitational force
4) resultant forces acting on satellite

Q 78: The tension in the cable supporting a life is more when the lift is _____.

Options:
1) moving downwards with uniform velocity
2) moving upwards with uniform velocity
3) stationary
4) moving upwards with acceleration

Q 79: For steel, the ultimate strength in shear as compared to ultimate strength in tension is _____.

Options:
1) same

2) 1/2
3) 1/3
4) 2/3

Q 80: In a simply supported beam, where the shear force is zero, the bending moment will be _____.
Options:
1) zero
2) maximum
3) minimum
4) zero or minimum

Q 81: The stress in a body due to suddenly applied load compared to when it is applied gradually is _____.
Options:
1) same
2) half
3) two times
4) four times

Q 82: Modulus of rigidity is defined as the ratio of _____.
Options:
1) longitudinal stress and longitudinal strain
2) volumetric stress and volumetric strain
3) lateral stress and lateral strain
4) shear stress and shear strain

Answer: shear stress and shear strain

Q 83: The intensity of stress which causes unit strain is called _____.
Options:
1) unit stress
2) bulk modulus
3) modulus of rigidity
4) modulus of elasticity

Q 84: The property of a material by virtue of which a body returns to its original shape after removal of the load is called _____.
Options:
1) Plasticity
2) Elasticity
3) Ductility
4) Malleability

Q 85: For which material the Poisson’s ratio is more than unity?

1. steel
B. copper
C. aluminium
D. cast iron
Options:
1) only A
2) only B
3) only C
4) None of these

Q 86: A beam is loaded as cantilever. If the load at the end is increased, the failure will occur _____.

Options:
1) in the middle
2) at the tip below the load
3) at the support
4) anywhere

Q 87: At the principal planes _____.

Options:
1) the normal stress is maximum or minimum and the shear stress is zero
2) the tensile and compressive stresses are zero
3) the tensile stress is zero and the shear stress is maximum
4) no stress acts

Answer: the normal stress is maximum or minimum and the shear stress is zero

Q 88: Two wires AO and BO support a vertical load W at O as shown in the figure below. The wires are of equal length cross sectional area. The tension in each wire is equal to:

Options:
1) W/2
2) W
3) √2W
4) W/√2

Q 89: A weight of 500 kg is held on a smooth plane, inclined at 30o to the horizontal by a force P acting 30o above the plane as shown in the figure below. The reaction of plane on the weight will be:

Options:
1) 500 N
2) 250 N
3) 476 N
4) 288 N

Q 90: Given figure shows a quick return mechanism. The crank OA rotates clockwise uniformly. OA = 2 cm. OO’ = 4 cm. The ratio of time for forward motion to that for return motion is:

Options:
1) 0.5
2) 2
3) √2
4) 1

Q 91: Binding wire used to support the joints for soldering is made of _____.
Options:
1) aluminium
2) copper
3) soft iron
4) mild steel

Q 92: Which of the following is not a casting process?

Options:
1) Carthias process
2) extrusion
3) semi-centrifuge method
4) slush process

Q 93: Carburising flame is used to weld metals like _____.

Options:
1) steel
2) copper and brass
3) aluminium, nickel, monel etc.,
4) carburised steel

Q 94: The most commonly used flame in gas welding is
A. Neutral
B. Oxidising
C. Carburising
Options:
1) only A
2) only B
3) only C
4) only A and B

Q 95: In braze welding, the filler metal is
A. Distributed by capillary attraction
B. Melted and deposited at the point where the weld is to be made
C. Not required
Options:
1) only A
2) only B
3) Both A and B
4) only C

Q 96: Magnetic arc blow is _____.
Options:
1) a recent welding technique
2) used to weld materials
3) occurs when welding near equator
4) phenomenon of occurrence of splatter because of magnetic fields created in d.c. arc welding

Answer: phenomenon of occurrence of splatter because of magnetic fields created in d.c. arc welding

Q 97: Preheating is essential in welding _____.
Options:
1) high speed steel
2) stainless steel
3) cast iron
4) german silver

Q 98: Tool in the case of ultrasonic machining is made of _____.
Options:
1) HSS
2) diamond
3) brass or copper
4) stainless steel

Q 99: Thread rolling is somewhat like _____.
Options:
1) cold extrusion
2) cold machining
3) cold rolling
4) cold forging

Q 100: The fatigue strength of metal is improved by setting up compressive stresses in the surface by a process known as _____.
Options:
1) lancing
2) shot-peening
3) hemming
4) slugging